Answer:
490N
Explanation:
Given that,
Mass of a skydiver, m = 50 kg
Buoyant force = 20 N
When the skydiver reaches the terminal velocity, net force on her is equal to 0. So, air drag is equal to the weight of the skydiver.
D = mg
Putting all the values,
D = 50 × 9.8
D = 490 N
So, the force of air resistance is 490 N.
A freshly prepared sample of radioactive isotope has an activity of 10 mCi. After 4 hours, its activity is 8 mCi. Find: (a) the decay constant and half-life T1/2; (b) How many atoms of the isotope were contained in the freshly prepared sample? (c) What is the sample's activity 30 hours after it is prepared?
Answer:
(a). The decay constant is [tex]1.55\times10^{-5}\ s^{-1}[/tex]
The half life is 11.3 hr.
(b). The value of N₀ is [tex]2.38\times10^{11}\ nuclei[/tex]
(c). The sample's activity is 1.87 mCi.
Explanation:
Given that,
Activity [tex]R_{0}=10\ mCi[/tex]
Time [tex]t_{1}=4\ hours[/tex]
Activity R= 8 mCi
(a). We need to calculate the decay constant
Using formula of activity
[tex]R=R_{0}e^{-\lambda t}[/tex]
[tex]\lambda=\dfrac{1}{t}ln(\dfrac{R_{0}}{R})[/tex]
Put the value into the formula
[tex]\lambda=\dfrac{1}{4\times3600}ln(\dfrac{10}{8})[/tex]
[tex]\lambda=0.0000154\ s^{-1}[/tex]
[tex]\lambda=1.55\times10^{-5}\ s^{-1}[/tex]
We need to calculate the half life
Using formula of half life
[tex]T_{\dfrac{1}{2}}=\dfrac{ln(2)}{\lambda}[/tex]
Put the value into the formula
[tex]T_{\dfrac{1}{2}}=\dfrac{ln(2)}{1.55\times10^{-5}}[/tex]
[tex]T_{\dfrac{1}{2}}=44.719\times10^{3}\ s[/tex]
[tex]T_{\dfrac{1}{2}}=11.3\ hr[/tex]
(b). We need to calculate the value of N₀
Using formula of [tex]N_{0}[/tex]
[tex]N_{0}=\dfrac{3.70\times10^{6}}{\lambda}[/tex]
Put the value into the formula
[tex]N_{0}=\dfrac{3.70\times10^{6}}{1.55\times10^{-5}}[/tex]
[tex]N_{0}=2.38\times10^{11}\ nuclei[/tex]
(c). We need to calculate the sample's activity
Using formula of activity
[tex]R=R_{0}e^{-\lambda\times t}[/tex]
Put the value intyo the formula
[tex]R=10e^{-(1.55\times10^{-5}\times30\times3600)}[/tex]
[tex]R=1.87\ mCi[/tex]
Hence, (a). The decay constant is [tex]1.55\times10^{-5}\ s^{-1}[/tex]
The half life is 11.3 hr.
(b). The value of N₀ is [tex]2.38\times10^{11}\ nuclei[/tex]
(c). The sample's activity is 1.87 mCi.
A racehorse coming out of the gate accelerates from rest to a velocity of 12.0
m/s due west in 2.30 s. What is its average acceleration?
27.6 m/s^2
5.22 m/s^2
-5.22 m/s^2
-27.6 m/s^2
-0.19 m/s^2
O 0.19 m/s^2
Answer:
5.22 m/s²
Explanation:
From the question given above, the following data were obtained:
Initial velocity (u) = 0 m/s
Final velocity (v) = 12 m/s
Time (t) = 2.3 s
Acceleration (a) =.?
Acceleration is defined as the change of velocity with time. Mathematically, it is expressed as:
Acceleration (a) = final velocity (v) – initial velocity (u) / time (t)
a = (v – u) /t
With the above formula, we can obtain the acceleration of the racehorse as follow:
Initial velocity (u) = 0 m/s
Final velocity (v) = 12 m/s
Time (t) = 2.3 s
Acceleration (a) =.?
a = (v – u) /t
a = (12 – 0) / 2.3
a = 12 /2.3
a = 5.22 m/s²
Therefore, the average acceleration of the racehorse is 5.22 m/s²
4. A cylindrical tube has a length of 14.4cm and a radius of 1.5cm and is filled with a colorless gas. If the density of the gas is known to be 0.00123g/cm', what is the mass of the gas in the tube in mg?
Answer:
Mass, m of gas is 0.2504 grams.
Explanation:
First, we need to solve for the volume of the cylindrical tube.
Volume of cylinder is given by the formula;
[tex] V = 2\Pi r^{2}h[/tex]
Where, V represents volume.
π represents pie
r represents radius.
h represents height or length.
Given the following data;
Radius, r = 1.5cm
Length, h = 14.4cm
Density, d = 0.00123g/cm³
Substituting into the equation;
[tex] V = 2 * 3.142 * (1.5)^{2}14.4[/tex]
[tex] V = 2 * 3.142 * 2.25 * 14.4[/tex]
[tex] V = 203. 6016[/tex]
Therefore, the volume of the cylindrical tube is 203. 6016cm³
Density can be defined as mass all over the volume of an object.
Simply stated, density is mass per unit volume of an object.
Mathematically, density is given by the formula;
[tex]Density = \frac{mass}{volume}[/tex]
[tex] Mass = density * volume [/tex]
Substituting into the equation, we have;
[tex] Mass = 0.00123 * 203. 6016 [/tex]
Mass = 0.2504g.
HEY CAN ANYONE PLS ANSWER DIS!!!!!!!!!!!
Answer:
Planetary Model of the Hydrogen Atom
Anne Marie Helmenstine, Ph. D. The Bohr Model has an atom consisting of a small, positively charged nucleus orbited by negatively charged electrons. Here's a closer look at the Bohr Model, which is sometimes called the Rutherford-Bohr Model.
Explanation:
Answer:
planetary model
Explanation:
Niels Bohr proposed the Bohr Model of the Atom in 1915. ... The Bohr Model is a planetary model in which the negatively charged electrons orbit a small, positively charged nucleus similar to the planets orbiting the sun (except that the orbits are not planar).
Calculate the slope of the line on the graph.
Answer: 5
Explanation: rise over run. 25/5 = 5
Why does sound travel slower at a cold temperature?
Sound moves faster in warmer air than colder air the way bends away from the warm air and back towards of air.
Answer:
Sound travels slower in cold temperatures than in hot temperatures because the particles in cold air are more closely compacted together and move slower compared to the particles of hot air. Thus the sound, vibrations of particles in the atmosphere, will travel slower.
In a food chain, consumers gather energy by _______. a. consuming organisms at a lower trophic level b. consuming organisms at a higher trophic level c. decomposing dead organic matter d. absorbing sunlight directly Please select the best answer from the choices provided A B C D
Answer:
a. consuming organisms at a lower trophic level.
Explanation:
A food chain shows how various organisms are related to each other as per the food they eat. Each level of a food chain refers to a distinct trophic level.
Food chain is basically related to transfer of matter and energy from organism to organism in the form of food.
In a food chain, consumers gather energy by consuming organisms at a lower trophic level
Answer:
a. consuming organisms at a lower trophic level.
Explanation: took the unit test
Write a brief summary of table tennis or tennis
Answer:
A point is won by a player when the opponent cannot hit the ball with a racket over the net and onto the other side of the table. Each game is won by being the first player to win 11 points, and be at least 2 points ahead of their opponent. The equipment needed to play table tennis would be a table, rackets, and balls. Some of the rules are no hand-on table (even leaning your hands on the table is not allowed!) Also, if the ball hits the net, you have to serve again.
What groups of animals are heterotrophs?
a.) herbivores
b.) carnivores
c.) omnivores
d.) all the above
Answer:
All of the above.
Explanation:
As a review, remember that carnivores eat other animals and omnivores eat both plants and animals. There is yet another term used when talking about food chains, the word heterotroph. Anything that is not an autotroph is a heterotroph. The word means “other feeding” or feed off of others.
which other team sport basketball is the most like.
hi
Answer: mmm... If you mean most like Basketball it's net ball but i don't know much about Basket ball teams
Explanation:
What is the design process (Engineering Design Process) 5 sentences
Which statement is true about magnetic field lines?
O A. They point toward the north pole of a magnet and away from the
south pole.
OB. They point toward the south pole of a magnet and away from the
north pole
O C. They loop from the south pole to the south pole and from the
north pole back to the north pole.
OD. No consistent pattern exists in the lines.
Answer:
It’s option B
Explanation:
Magnetic field lines are defined to have the direction that a small compass points when placed at a location. If small compasses are used to map the magnetic field around a bar magnet, they will point in the directions shown: away from the north pole of the magnet, toward the south pole of the magnet.
The magnetic field lines are the points towards the south pole of magnet and are away from the north pole. Thus, option B is correct.
What are magnetic field lines?A North magnetic pole would move along magnetic field lines, which are lines drawn in a magnetic field. Magnetic lines of force are another name for the magnetic field lines.
The north pole serves as the starting point for magnetic lines of force, which end at the south pole. They won't ever cross over each other.
Small compasses will point away from the magnet's north pole and toward its south pole when used to map the magnetic field surrounding a bar magnet.
Therefore, the magnetic field lines are given to have direct attention away from the north pole of a magnet and toward its south pole.
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Help mee what molecule is this
how am I supposed to know
A projectile is launched horizontally at a speed of 30m/s from a 100m tall building. how much time it will take to reach the ground?
Answer:
3.3 seconds I believe
Explanation:
witch element is the most prevalent in the human body a)nitrogen,b)hydrogen,c)carbon,d)oxygen
What theory explains the main cause of mountain building, earthquakes, and volcanic eruptions on Earth?
Group of answer choices
the scientific theory of Earth's shift
the scientific theory of magnetism
the scientific theory of Earth's layers
the scientific theory of plate tectonics
Answer:the scientific theory of plate tectonics I believe
Explanation:
witch of the following questoons would you expect to see on an interest inventory
Answer: Do you like science experiments ? 1)
Would You enjoy reading a fashion magazine? 2)
Explanation:
Describe a circumstance where you want friction to work against Newton’s First Law.
Answer:
If I was riding my bicycle, and there was no friction to work against Newton's First Law, I'd give a first push, and I would never be able to turn or stop.
Explanation:
PLEASE PLS PLS ANSWER ASAP
Answer:
Explanation:
24 i think
Answer:
B. 24
Explanation:
There are 24 atoms in one molecule of C6 H12 06. This chemical compound is made up of 6 atoms of carbon, 12 atoms of hydrogen, and 6 atoms of oxygen. We find the number of atoms by adding these numbers up. We than get:
6 + 12 + 6 = 12 + 12 = 24
Therefore, there are 24 atoms in the following chemical formula.
please help im dying
The gradual change in a species over time is called
a.
mutation.
b.
evolution.
c.
migration.
d.
variation.
PLZ HURRY WILL GIVE BRAINLIEST
Answer: B. Evolution
Explanation:
As species grow older over time they will gradually evolve through natural selection and evolution.
The gradual change in a species over time is known as evolution (b).
The process of evolution occurs through several mechanisms, including mutation, migration, and natural selection.
Mutation (a) is the spontaneous change in the genetic material of an organism. These changes can result in new traits that may be advantageous, disadvantageous, or neutral for survival. When mutations occur, they can introduce genetic variation within a population, which serves as the raw material for evolution.
Natural selection is a crucial factor driving evolution. Individuals with advantageous traits that better suit their environment are more likely to survive and reproduce, passing on these advantageous traits to their offspring. Over generations, the frequency of beneficial traits increases in the population, leading to the adaptation and evolution of the species.
Variation (d) encompasses the differences in physical traits and genetic makeup among individuals within a population. This variation is essential for evolution to occur since it provides the raw material for natural selection to act upon.
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Question 1 of 20
Two bicyclists are accelerating forward at the same rate. Biker 1 has less
mass than Biker 2. Which statement describes the net force on the bikers?
A. The net forely on both bikers is changing.
B. Both bikers experience the same net force.
C. The net force on Biker 1 is in the backwards direction.
D. The net force on Biker 2 is greater than on Biker 1.
Answer:
The net force on biker 2 is greater than on biker 1
Explanation:
Apex;)
Answer:
D. The net force on biker 2 is greater than on biker 1
Explanation:
An object has an acceleration of 6m/s/s. If the net force was tripled and the mass was doubled, then the new acceleration would be
list 3 lessons we learned from history to handle pandemic
Answer:
1- impact
2. Inequalities
4. Controllability
Explanation:
state the various use of a periscope
Answer:
the periscope is an instrument for observation over, around or through the object, obstacle or condition that prevents direct line-of-sight observation from the observer's current position.
Explanation:
the periscope is used to monitor the dangerous chemical reactions in the laboratory and they are used in observing the nuclear.
Answer:
A periscope is used to see objects over the heads of a crowd.It is used by soldiers sitting in a bunker to observe and view the opponents' activities over the ground.It is used by a navy officer sitting in a submarine to see ships over the surface of the water in the sea.It is also useful in submarines to determine the distance of the torpedo and decide the right time for an attack.can you help me doing an essay about actual self
Answer:
yes absolutely
Explanation:
why not
You're driving your car at a constant speed in a straight line which of the following can be used to cause your car to experience a centripetal acceleration
A)brake pedal
B) steering wheel
C)gas pedal
D)All of the above
matter makes up all ? and ?
the solubility of sugar is 30 degree Celsius at 220 what does it mean
Answer:
So, that if you put 100 mL of 30 degree water in a beaker, you could add up to 220 grams of sugar and it would eventually dissolve. In other words, that mass of sugar should dissolve in 100 mL of water to make a solution that is just saturated.
The solubility of sugar is 30° C at 220. This means 220g of sugar is dissolved in 100g of solvent to make the saturated solution at 30° C. Solutions.
What is the solution?Most frequently, the solubility is represented in terms of mass per volume of water. Solubilities are frequently stated as g/100 mL, g/100 g, or g/L of water.
The ratio you provided is probably 1 g of sugar to 100 mL of water. In other words, if you put 100 mL of water at 30 degrees in a beaker, you could add up to 220 grams of sugar, and it would finally dissolve.
To generate a solution that is just saturated, the mass of sugar should dissolve in 100 mL of water.
Therefore, at 220 degrees, sugar dissolves at 30 degrees. This indicates that to create the saturated solution at 30° C, 220g of sugar must be dissolved in 100g of solvent.
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I will give you more points if you want!!! :)
But first please answer the following question!
Answer:
thank you very much for giving me points.
Explanation:
I really appreciate it so muchhhhh so muchhhh thanks again