A parallel laser beam of width w1 is incident on a two lens system as shown below. Each lens is converging. The second lens has a larger focal length than the first (f2>f1). 1) What does the beam look like when it emerges from the second lens? O The beam is converging O The beam is diverging O The beam is parallel to the axis with a width < W1 O The beam is parallel to the axis with a width = w1 O The beam is parallel to the axis with a width > W1

Answers

Answer 1

When it emerges from the second lens, the beam seems to be parallel to the axis and wider than W1. A two lens system is incident on by a parallel laser beam of width w1, as shown below.

Every lens is focusing together. Pole The pole of a lens is the centre of its spherical refracting surface. the location where the lens's surface and primary axis converge. Vision Center The term "Optical Center" refers to the location on the primary axis that is in the middle of the lens. The transmissive optical device known as a lens employs refraction to focus or disperse a light beam. The only component of a basic lens is a single transparent piece (elements).

Learn more about light beam here

https://brainly.com/question/16815756

#SPJ4

A Parallel Laser Beam Of Width W1 Is Incident On A Two Lens System As Shown Below. Each Lens Is Converging.

Related Questions

I need help on a homework question.

Chris shines a white light onto a surface, and the surface appears to be green. What color will the surface appear if he shines a combination of blue and green light on the surface?

A. brown
B. white
C. green
D. black

Answers

Answer:

green

Explanation:

the the board is going to be green

Answer:

The surface will appear green if he shines the combination of blue and green light.

Explanation:

When Chris shines white light on the surface it appears green it means the surface is scattering only green light.it is called scattering of light.The material of the surface is absorbing rest of the colors.What is scattering of light ?

When light passes through a medium , the particles of the medium or surface allows to reflect only a particular color ( wavelength), this phenomenon is called scattering of light.

Hence the surface will appear green .

Read it also for better understanding:-

https://brainly.com/question/9922540

#SPJ2

Which 5 are examples of locomotor movements? Select all that apply.
Question 1 options:

Hopping

Galloping

Sitting

Sleeping

Walking

Running

Skipping

Eating

Answers

Answer:

Five examples of locomotor movements are:

Hopping

Galloping

Walking

Running

Skipping

Explanation:

I hope it helps ❤❤

Atoms of which pair of elements will form covalent bonds in a compound? ASAP PLZ

A. Li and Al
B. C and O
C. Co and Fe
D. Na and F

Answers

Answer:B

Explanation:

C and O

Atoms of C and O pair of elements will form covalent bonds in a compound.Therefore the correct option is B.

What is a Chemical compound?

The chemical compound is a combination of two or more  either similar or dissimilar chemical elements

for example, H₂O is a chemical compound made up of two oxygen atoms and a single hydrogen atom.

These chemical compounds are formed because of different types of bonds between the constituents elements ,the chemical bonds are mainly ionic bonds, covalent bonds,s, and hydrogen bonds.

Ionic bonds are formed due to the transfer of electrons between two bond forming pairs differentiated by their electronegativity.

Covalent bonds are formed by the sharing of electrons.Generally organic compound are formed as the reason of covalent bonds.

The carbon and oxygen atoms share their valence electrons to form a covalent bond, therefore the correct option is B.

Learn more about a chemical compound from here

brainly.com/question/12166462

#SPJ5

HELP ITS FOR SCIENCE
1. Explain why a wrecking ball can destroy a building, but a yo-yo can’t. Use the term kinetic energy in your explanation.

2. How is speed related to kinetic energy?

Answers

Answer:

A wrecking ball has the capability to destroy a building due to the greater mass and kinetic energy than the yo-yo.

Write the laws of reflection​

Answers

Answer:

i) Angle of Reflection = Angle of Incident

ii) Total Angle = 2x Angle of reflection/incidence

iii) The incident ray, reflected ray and the point of incidence lie in the same plane

Hope it helped u,

pls mark as the brainliest        - Ayaan707 for help :) -

^_^

a 6.25-gram bullet traveling at 365 ms strikes and enters a 4.50-kg crate. The crate slides 0.15 m along a wood floor until it comes to rest. What is the change in kinetic energy of the system after the collision

Answers

Answer:

the change in kinetic energy of the system is 0.577 J

Explanation:

Given;

mass of the bullet, m₁ = 6.25 g = 0.00625 kg

initial velocity of the bullet, u₁ = 365 m/s

mass of the crate, m₂ = 4.5 kg

initial velocity of the crate, u₂ = 0

distance moved by the system after collision, d = 0.15 m

Determine the final velocity of the system after collision;

m₁u₁ + m₂u₂ = v (m₁ + m₂)

0.00625 x 365 + 4.5 x 0 = v(0.00625 + 4.5)

2.2813 + 0 = v(4.5063)

2.2813 =  v(4.5063)

v = 2.2813 / 4.5063

v = 0.506 m/s

The change in kinetic energy of the system after collision is calculated as;

ΔK.E = ¹/₂ (m₁ + m₂)v²

ΔK.E =  ¹/₂ (4.506) x 0.506²

ΔK.E = 0.577 J

Therefore, the change in kinetic energy of the system is 0.577 J

Energy Transformation and Conservation

Explain how different forms of energy are related.

Answers

Answer:

Energy transformation is when energy changes from one form to another – like in a hydroelectric dam that transforms the kinetic energy of water into electrical energy. While energy can be transferred or transformed, the total amount of energy does not change – this is called energy conservation.

Explanation:

What is electronegativity​

Answers

Electronegativity is a measure of an atom's ability to attract shared electrons to itself. On the periodic table, electronegativity generally increases as you move from left to right across a period and decreases as you move down a group.

Young David who slew Goliath experimented with slings before tackling the giant. He found that he could revolve a sling of length 0.600 m at the rate of 5.00 rev/s. If he increased the length to 0.900 m, he could revolve the sling only 3.00 times per second. (a) What is the speed of the stone for each rate of rotation

Answers

Answer:

Explanation:

For circular motion of stone the formula is

v = ω R where ω is angular velocity , v is linear velocity .

For first motion ,

R = length of sling = .6 m

ω = 2π n , n is no of revolution per second

ω = 2 x 3.14 x 5 = 31.4 rad /s

v = 31.4 x .6 = 18.84 m /s

For second  motion ,

R = length of sling = .9 m

ω = 2π n , n is no of revolution per second

ω = 2 x 3.14 x 5 = 31.4 rad /s

v = 31.4 x .9 = 28.26  m /s

A child holds a sled at rest on frictionless snow covered hill. if the sled weighs 77N,find the force T exerted by the rope on the sled and the force n exerted by the hill on the sled​

Answers

Answer:62

Explanation:

The weight of the sled is 77 N. The force by the hill on the sled is equal to its weight that is 77 N. Then the tension force exerted by the rope on the sled is being 77N sin θ, where θ be the angle of inclination.

What is force?

Force is an external agent acting on an object to change its motion or to deform it. There are various kinds of force like magnetic force, tension force, frictional force, gravitational force etc.

The weight that an object experience on earth is due to the gravitational force. The force that is exerted by a rope on an object is tension force since it is pulling from a side.

The normal force by the hill on the sled is equal to its weight that is 77 N. The tension force on the sled by the rope is dependent on the angle of inclination θ. If know the angle we can find T by the equation:

T = 77 sin θ.

Find more on tension force:

https://brainly.com/question/29124835

#SPJ5

1. A wheel with spokes of length r has four masses
attached at various points where the spokes intersect the
circumference of the wheel. The wheel and spokes are
massless and spokes are all 30° apart. Determine the net
torque on the wheel.
(A) Zero (B) 22 (C) 13/2
(D) 1

Answers

I can help here 20 q 45

Can someone help please

Answers

Answer:

The average blood speed is 0.39 m/s

Explanation:

According to Poiseuille’s law, the volume flow rate, Q (m³/s) of a fluid of

viscosity η through a tube or pipe of radius r and length L is:

Q = πr⁴ΔP/8ηL

where ΔP is the change in pressure or pressure difference of the fluid; L is length of the pipe

Also, the volume flow rate, Q, is related to the average velocity v, by the formula:

Q = Av

where A is the cross-sectional area of the pipe; A = πr²

Q = πr²v

Thus, the Poiseuille’s becomes: πr²v = πr⁴ΔP/8ηL

v = r²ΔP/8ηL

From the given values:

r = 2.5 mm = 0.0025 m

L = 15 cm = 0.15 m

ΔP = 380 Pa

η = 5 * 10⁻³ Pa.s

substituting the given values in the equation

v = {(0.0025)² * 380} / (8 * 5 * 10⁻³ * 0.15)

v = 0.39 m/s

Therefore, the average blood speed is 0.39 m/s

A question to think about on units: Suppose we wanted to exchange scientific information with a newly discovered species of intelligent life living on a planet orbiting the star Alpha Centauri. And suppose that our new friends have managed to become fluent in our language, but have not yet had the opportunity to visit the Earth. Which of the following statements would they understand?

a. The mass of the electron is 9.10938188 x 10^-31.
b. The speed of light is 2.99792458 x 10^8 meters/second.
c. The ratio of the proton's mass to the electron's mass is 1836.153. Explain your reasoning

Answers

Answer:

b. The speed of light is 2.99792458 x 10^8 meters/second.

Explanation:

Speed of light is a universal constant and its value is same throughout the universe . So alien living near Alpha Centauri will quickly understand about it . But other statements are not universal . Mass of electron can vary  as per relativistic formula of Einstein . Similarly , mass of proton can also vary according to relativistic concept . It depends upon the velocity of particle . So, the ratio of mass of proton and mass of electron will also vary from one star to another .

a surfer talks about riding a 20-foot wave. Which measurement of waves is the surfer describing?

frequency
amplitude
wavelength
speed

60 POINTS!!

Answers

Frequency I think that’s correct

Answer:

C. Amplitude

Explanation: Amplitude is the maximum displacement from the equilibrium of a wave. Basically the height.   

what is the relationship between net impulse and change in momentum?

Answers

Answer:

impulse equals the average net external force multiplied by the time this force acts. It is equal to the change in momentum.

Explanation:

Example 2.1
A car travels at an average speed of 100 kmh-1
what distance does it cover in 5 minutes?​

Answers

Answer:

5 min 20 km --------

Explanation:

5 min 20 km --------

Tyler and Jim race each other up a mountain on their bicycles. Tyler rides a road bike on the switchbacks of the twisting and turning mountain road. Jim rides a mountain bike and follows a direct, but steeper, straight-line path up the mountain. They start at the same time and place at the bottom of the mountain and finish at the same time and place at the top of the mountain. From start to finish a. whose distance traveled was longer? b. whose displacement was longer? c. which rider had the faster average speed? d. which rider had the faster average velocity? e. who won the race?

Answers

Answer:

Explanation:

Displacement is minimum distance between initial and final point .

Distance is total length of path covered in a journey .

a )

Tyler covered a longer distance in the journey because total length of path covered by him is longer due to curved path .

b )

Both have same displacement , because minimum distance between initial and final point in both the case is same .

c )

average speed = distance / time

as time is same for both the case ,

average speed ∝ distance

As distance covered by Tyler is more , his average  speed is more .

d )

average velocity = displacement / time

As both displacement and time are same in both the case , average velocity in both the case is same .

e )

They start at the same time and place at the bottom of the mountain and finish at the same time , both have tie and nobody won the race , in spite of speed of Tyler being greater  .

A proton accelerates from rest in a uniform electric field of 664 N/C. At some later time, its speed is 1.46 106 m/s. (a) Find the magnitude of the acceleration of the proton. m/s2 (b) How long does it take the proton to reach this speed? µs (c) How far has it moved in that interval? m (d) What is its kinetic energy at the later time? J

Answers

Answer:

Explanation:

In an electric field E force on charge q

F = Eq , acceleration a = Eq / m

a = 664 x 1.6 x 10⁻¹⁹ / 1.67 x 10⁻²⁷

= 636.16 x 10⁸ m /s²

b )

initial velocity u = 0

final velocity v = 1.46 x 10⁶ m/s

v = u + at

1.46 x 10⁶ = 0 + 636.16 x 10⁸ x t

t = 2.29 x 10⁻⁵ s

c )

s = ut + 1/2 a t²

= 0 + .5 x 636.16 x 10⁸ x (  2.29 x 10⁻⁵ )²

= 1668 x 10⁻²

= 16.68 m

d )

Kinetic energy = 1/2 m v²

= .5 x 1.67 x 10⁻²⁷ x ( 1.46 x 10⁶ )²

= 1.78 x 10⁻¹⁵ J .

The name of the SI unit for magnetic field strength, such as that created around a current-carrying wire, is the
.

Answers

Tesla. SI

The unit of magnetic field is tesla. It is the SI unit of magnetic field. Magnetic field is the measure of magnetic flux (Φ) per unit area. 1tesla=1wb/m
2
.

The name of the SI unit for magnetic field strength is Tesla. Magnetic fields are formed by moving electric charges.

What is Magnetic field strength?

Magnetic field strength alludes to an actual amount that is utilized as one of the essential proportions of the power of the attractive field.

The SI unit of attractive field is tesla (T). 1 Tesla is defined as the magnetic field that carries 1C charge at the speed of 1m/s which is perpendicular to the force of 1 N.

Find more information about magnetic field strength here:

brainly.com/question/18651668

An electrically charged object creates an electric field. The electric potential due to this object:Group of answer choicesis a vector that points either towards or away from the object, depending on the sign of the chargeis a vector that makes circular paths around the objectis a non-negative scalaris a scalar but will be positive or negative depending on the sign of the charge

Answers

Answer:

It's a scalar but will be positive or negative depending on the sign of the charge.

Explanation:

The electric potential, at a given point, can be defined as the work per unit charge needed to bring a positive test charge from infinity to this point.It's positive if the charge creating the potential is positive (because it's needed that an external force do work on the test charge against the electric field that repels the positive charge).It's negative if the charge creating the potential is negative, because in this case the field will attract the positive test charge.

2. The storage in a river reach at a specified time is 3 hectare-meters. At the same instant, the inflow to the reach is 15 m3/s and the outflow is 20 m3/s. One hour later, the inflow is 20 m3/s and the outflow is 20.5 m3/s. Determine the change in storage in the reach that occurred, during the hour. What is the storage at the end of the hour? (1 hectare = 10000 m2).

Answers

Answer:

The change in storage in the reach that occurred, during the hour  = 43200 m3

The storage at the end of the hour = 129600 m3

Explanation:

Given

Storage =  3 hectare-meters

Inflow volume = 15 m3/s

Outflow volume = 20 m3/s

Storage in one hour of change

Inflow volume = 20 m3/s

Outflow volume = 20.5 m3/s

Outflow volume - Inflow volume = 0.5 m3/s = 0.5 * 24*60 * 60 = 43200 m3

Storage at the end of one hour

43200 m3 + (20-15) * 24*60 * 60 = 129600 m3

Select the correct answer.
The oceanic Nazca plate is being subducted beneath the continental South American plate. Which type of plate boundary is this?
OA continental-oceanic convergent
ОВ. oceanic-oceanic convergent
OC divergent
OD. strike-slip
ОЕ.
transform
Reset
Next

Answers

Answer:

A. continental-oceanic convergent

Explanation:

I knew it couldn't be B because it's oceanic and continental, not oceanic and oceanic.

Next, I noticed the word convergent, which implies "coming together" to me.

I looked it up and noticed the term convergent referred to a plate boundary where a plate slips under (subducted) another, so I knew it was A.

Hopefully, this helps you understand the question better. Have a great day!

On a car trip you drive for 2 hours and 41 minutes on a highway at a speed of 107.0 km/h. Then you stop at a gas station to fill up your tank. You also eat a quick lunch. The whole break lasts 23 minutes. After the break you start your engine up and you switch to a state road. You drive for another 3 hours and 31 minutes at a speed of 67.0 km/h before you arrive to your destination. What was your average speed for the whole trip with the lunchbreak included

Answers

Answer:

v = 79.3 km/h

Explanation:

By definition, the average speed, is the quotient between the total distance traveled and the time needed to travel that distance.The total time, is the sum of three times: one while driving before stopping at the gas station (t₁), the time spent there (t₂) and the time since leaving the gas station until reaching the final destination (t₃) .Let's convert these times to seconds first:

      [tex]t_{1} = 161 min* \frac{60s}{1min} = 9660 s (1)[/tex]

      [tex]t_{2} = 23 min* \frac{60s}{1min} = 1380 s (2)[/tex]

      [tex]t_{3} = 211 min* \frac{60s}{1min} = 12660 s (3)[/tex]

      [tex]t_{tot} =t_{1} +t_{2} +t_{3} = 9660s + 1380s + 12660s = 23700s (4)[/tex]

In order to find the total distance traveled, we need to add the distance traveled before stopping at the gas station (x₁) and the distance traveled after leaving it (x₂).Applying the definition of average speed, we can find these distances as follows:

       [tex]x_{1} = v_{1} * t_{1} (5)[/tex]

       [tex]x_{2} = v_{2} * t_{3} (6)[/tex]

where v₁ = 107.0 km/h, and v₂= 67.0 km/hAs we did with time, let's convert v₁ and v₂ to m/s:

       [tex]v_{1} = 107.0 km/h*\frac{1000m}{1km}*\frac{1h}{3600s} = 29.7 m/s (7)[/tex]

      [tex]v_{2} = 67.0 km/h*\frac{1000m}{1km}*\frac{1h}{3600s} = 18.6 m/s (8)[/tex]

Replacing (7) and (1) in (5) we get x₁, as follows (in meters):

       [tex]x_{1} = v_{1} * t_{1} = 29.7 m/s * 9660 s = 286902 m (9)[/tex]

Doing the same for x₂ with (3) and (8):

       [tex]x_{2} = v_{2} * t_{3} = 18.6 m/s * 12660 s = 235476 m (10)[/tex]

Total distance traveled is just the sum of (9) and (10):

       [tex]x_{tot} = x_{1} +x_{2} = 286902 m + 235476 m = 522378 m (11)[/tex]

As we have already said, the average speed is just the quotient between (11) and (4), as follows:

       [tex]v_{avg} =\frac{\Delta x}{\Delta t} = \frac{522378m}{23700s} = 22.0 m/s (12)[/tex]

Converted back to km/h:

       [tex]v_{avg} = 22.0 m/s*\frac{1km}{1000m}*\frac{3600s}{1h} = 79.3 km/h (13)[/tex]

*How much energy is
transferred in lifting a 5 kg
Mass 3m​

Answers

Answer:

147 J

Explanation:

The energy transferred to potential energy is :

U = m * g * h = (5 kg) * (9.8 m/s^2) * (3 m) = 147 J

The steepness of a line on a graph is called the
O A. rise
OB. slope
C.
run
D. verticle axis

Answers

Answer:

slope

Explanation:

The slope is how how steep the line is.

Hrhrhebbsbsbsbbdbfbbfbfbdbdndndndndndndndndn Slope

convert 0.0345mW
to MW​

Answers

Answer:

3.45e-11MV

that is ur answer

Estimate the constant rate of withdrawal (in m3 /s) from a 1375 ha reservoir in a month of 30 days during which the reservoir level dropped by 0.75 m in spite of an average inflow into the reservoir of 0.5 Mm3 /day. During the month, the average seepage loss from the reservoir was 2.5 cm, total precipitation on the reservoir was 18.5 cm and the total evaporation was 9.5 cm

Answers

Answer:

Explanation:

1 ha = 10⁴ m²

1375 ha = 1375 x 10⁴ m² = 13.75 x 10⁶ m²

In flow in a month = .5 x 10⁶ x 30 m³ = 15 x 10⁶ m³

Net inflow after all loss = 18.5 - 9.5 - 2.5 cm = 6.5 cm = .065 m

Net inflow in volume = 13.75 x 10⁶ x .065 m³= .89375 x 10⁶ m³

Let Q be the withdrawal in m³

Q - 15 x 10⁶ - .89375 x 10⁶ = 13.75 x 10⁶ x .75 = 10.3125 x 10⁶

Q = 26.20 x 10⁶ m³

rate of withdrawal per second

= 26.20 x 10⁶ / 30 x 24 x 60 x 60

= 26.20 x 10⁶ / 2.592 x 10⁶

= 10.11 m³ / s

The rate of withdrawal is 10.11 cubic meter per second

Given-

Total reservoir is 1375 hectare. which is equal to [tex]1375\times 10^4[/tex] meter square.

The average seepage loss from the reservoir is 2.85 cm or 0.0285 m.

Total precipitation on the reservoir is 18.5 cm or 0.185 m.

Total evaporation is 9.5 cm or 0.085 m.

The average inflow into the reservoir is [tex]0.5\times10^6[/tex] cubic meter per day.

The total inflow in a month can be calculate is

[tex]=0.5\times 30=1500\times10^4[/tex]

Net inflow is equal to the total precipitation on the reservoir subtract by all the losses.It can be represent as,

[tex]Q_{net}=0.185 - 0.095 - 0.025[/tex]

[tex]Q_{net}=0.065[/tex]

Total volume inflow is equal to the product of net inflow and total reservoir,

[tex]V_{net} =1375\times 10^4\times Q_{net}[/tex]

[tex]V_{net} =1375\times 10^4\times 0.065[/tex]

[tex]V_{net} =89.375[/tex]

The constant rate of withdrawal in cubic meter can be calculated by adding the net inflow in a month, total volume inflow and the reservoir.

[tex]Q=1375\times 10^4\times 0.75+89.375\times 10^4+1500\times10^4[/tex]

[tex]Q=2620\times10^4[/tex]

For per second withdrawal,

[tex]Q=\dfrac{2620\times10^4}{30\times24\times60\times60}[/tex]

[tex]Q=10.11[/tex]

Hence, the rate of withdrawal is 10.11 cubic meter per second.

For more about the flow, follow the link below,

https://brainly.com/question/1410288

Question 15 of 25
What is the period of a wave that has a frequency of 30 Hz?

Answers

Answer:

0.033 seconds

Explanation:

Period = 1/30 = 0.033 seconds

Answer:

The answer is 0.03 s

Explanation:

A.P.E.X.

Help with both questions I’ll mark brainliest

Answers

Answer:

gas, liquid, solid

sound cannot travel in space

Answer:

1. gas , liquid , gas

2.sound cannot travel in space

Scientists have investigated how quickly hoverflies start beating their wings when dropped both in complete darkness and in a lighted environment. Starting from rest, the insects were dropped from the top of a 50 - cm tall box. In the light, those flies that began flying 200 m s after being dropped avoided hitting the bottom of the box 87 % of the time, while those in the dark avoided hitting only 25 % of the time.

Required:
a. How far would a fly have fallen in the 200 ms before it began to beat its wings?
b. How long would it take for a fly to hit the bottom if it never began to fly? In seconds.

Answers

Answer:

Explanation:

a )

Hoverfly will fall with acceleration equal to g .

Initial velocity of fall of hoverflies u = 0

displacement ( vertical ) h = ?

time t = 0.2 s

acceleration due to gravity g = 9.8 m / s²

h = ut + 1/2 g t²

= 0 + .5 x 9.8 x .2²

= .196 m

= 19.6 cm

b )

Time taken to fall by 50 cm or 0.5 m under free fall from initial position .

.5 = 0 + .5 x 9.8 t²

t² = .1020

t = .319 s = 319 ms .

Other Questions
Examining different cells such as the plants, animal, and fungus cells. Identify the different organelles found in different cells and list the organelles and structures the characterize each of them. How are astronomers able to determine what elements are found in other stars and galaxies? FIND the MAIN IDEA OF THE TEXT Atkins agreed to testify against Manson in exchange for avoiding the death penalty. Her grand jury testimony led to Manson being arraigned for the murders on Dec. 11, 1969. Atkins later recanted her testimony, and her deal was revoked by the prosecutors [source: Steffens and Staples]. Linda Kasabian, who hadn't entered any of the houses or committed any murders, was granted immunity and testified for the prosecution during the trial. Determine the value of x.A) 4.96B) 2.90C) 11.62D) 0.73 What would the figure below look like after a reflection across the x-axis? Type the verb suggested by the related word(s).minimization; minimal: -a^2+7b^4-2c^3 if a= -4 b= -2 and c=-3 (02.04 LC)Powers shared by the national and state governments are called (3 points) Write the fraction in simplest form. *8/12 What was most unique about Steve'schildhood? 300x + 20 + 5x + 10 -40x2 = What is the best definition of federalism? Which of the following did Jackie Robinson do first? Played professional baseball for the Kansas City Monarch. Started playing professional baseball for the Brooklyn Dodgers. Joined the army and was honorably discharged. Discussed playing in the Major Leagues with Branch Rickey. Can anyone help with condensing this? In your own words, describe invention. Decide how important the setting is to the plot of following children's stories. If you are not familiar with a story, get a summary from the Internet and then decide how important the setting is to the story's plot. "Goldilocks and the Three Bears" : important of not important Mind lending me a hand When is the Glorious Mysteries of the Rsary Prayed? HELP PLEASE Find the surface area of the 3D shape. Simplify the following (c) 2( - 3) - 5[a - 2(a - 4)