A ball is gently dropped from a height of 20 m. If its velocity increases uniformly at the rate of 10m s -2 , with what velocity will it strike the ground? After what time will it strike the Ground?
Height,h= 20m
"gently dropped" means initial velocity, u, =0m/s
Uniform acceleration, g=10m/s²
using the formula v²=u²+2gs
Substituting, v²=0²+2*10*20
v²=400
v=
[tex] \sqrt{400} [/tex]
v=20m/s
Time, t at which is strike the ground
using the formula v=u+at
Substituting, 20=0+10t
20=10t
t=2s
This means that the bank strike the ground with a velocity of 20m/s in 2s.
A football player kicks a ball with a mass of .55 kg. The average acceleration of the football was 14.9 m/s2. How much force did the kicker supply to the football?
A. 35.24 N
B. 8.2 N
C. 35.24 m/s^2
D. 8.2 m/s^2
Answer:8.2N
Explanation:I did the quiz on k12 and that’s the answer i got :)
An ice skater initially skating at a velocity of 3 m/s speeds up to a velocity of 5 m/s. The momentum
of the skater
A Remains the same
B Increases
C Becomes zero
D Decreases
Answer:
B. Increases
Explanation:
Momentum is given as [tex]p=mv[/tex]. Since [tex]m[/tex] is maintained, as the velocity decreases, the momentum decreases, and similarly, as the velocity increases, the momentum increases.
What is the change in momentum of a 50. kg
woman goes from running at 8.0 m/s to 0.0
m/s?
Answer:
400 kg-m/s
Explanation:
Given that,
Mass of the woman, m = 50 kg
Initial velocity, u = 8 m/s
Final velocity, v = 0 m/s
We need to find the change in momentum of the woman. It can be given by :
[tex]\Delta p=m(v-u)\\\\=50\times (8-0)\\\\=400\ kg-m/s[/tex]
So, the change in momentum is 400 kg-m/s.
A student claims that any object in motion must experience a force that keeps it in motion. Do you agree or disagree?Explain your reasoning.
Answer:
i disagree because if you throw a ball in the air gravity will bring it down so only the force that moved it was needed.
Explanation:
How does friction affect energy
Answer:
Friction is a resistive force to motion. When two bodies move against each other some of the kinetic energy is converted to heat energy due to friction. This reduces the total kinetic energy in the system.
Explanation:
A box of weight 200N is placed on a ground of 20m square . Find the pressure
exerted by the box.
Answer:
10 Pascal
Explanation:
[tex]pressure =\frac{force}{area}[/tex]
[tex]pressure= \frac{200}{20}[/tex]
pressure = 10 Pa
Where do coaster cars have the least amount of potential energy?
Answer:
Gravitational potential energy is greatest at the highest point of a roller coaster and least at the lowest point.
What type of equipment do you need to play Petanque?
A broom and a stone
A metal ball and a wooden ball
Anet and a rattan ball
A rubber ball and a wooden bat
A metal ball and a wooden ball
hope it helps
What’s the meaning of Density
Answer:
d= m/v
density is mass per unit volume.
Density describes how tightly packed particles are so if something is more dense the particles are going to be packed closely together and if something is less dense they will be looser and not as tightly packed.
What is the thermal energy of an object?
the total kinetic energy of its particles
the total potential energy of its particles
its total temperature
the total kinetic and potential energies of its particles
Answer:
The total kinetic and potential energies of its particles
The thermal energy of an object is the:
D. the total kinetic and potential energies of its particles
What is thermal energy?Thermal energy is the sum of the kinetic and potential energy of all the particles in an object.
Examples are Exothermic chemical reactions, such as oxidation, which convert the potential energy of the materials into thermal kinetic energy, thus increasing the resulting temperature.
Thus, option D is correct.
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- A 9,300 kg. railroad car traveling at a velocity of 15m/s strikes a second boxcar
at rest. If the two cars stick together and move off with a velocity of 6m/s, what is the mass
of the second car?
Answer:
13950kg
Explanation:
If we make the system both railroad cars, we know that the momentum of the whole system doesn't change because the forces are internal.
Let a be the mass of the second car.
The original momentum is 9300*15 kg*m/s+ a*0 kg*m/s = 139500 kg*m/s
After sticking together, the momentum is (9300+a)kg*6m/s, which should be equal to 139500 kg*m/s
Therefore (9300+a)*6 = 139500
9300+a = 23250
a = 13950 kg
Will someone please look at my other questions
Answer:
eeeeeeeeeeeeeeeeeeeeeeeeeeeee
Explanation:
An induced charge is when charged particles can be attracted to neutral objects.
True or false?
Answer:
the answer is true Induction charging is a method used to charge an object without actually touching the object to any other charged object.
Explanation:
Real world System of equations
Drag the tiles to the correct boxes to complete the pairs. Match each expression to its simplified form.
Answer:
3a^5 - (-a^5) = 3a^5 + a^5 = 4a^5
6a^7 - 2a^7 = 4a^7
-3a^5 - (-2a^5) = -3a^5 + 2a^5 = -a^5
7a^7 - 8a^7 = -a^7
Answer:
here ya go
Explanation:
What energy transformation occurs when a coil of wire moves past a magnet? plz help :(
kinetic --> electric
electric --> kinetic
magnetic --> electric
kinetic --> potential
Answer:
kinetic energy to electrical energy.
WILL MARK BRAINLIEST
How much heat is required to raise the temperature of 150 grams of water from 15
C to 20 C, give that the specific heat of water is 4.18 J/g/C?
- 7.18 J
- 125 J
- 179 J
- 3,140 J
Answer:
aww that's simple! its B can i get brainliest? i really need some points rn <3
Explanation:
Answer:
B
Explanation:
the ... in an atom move about in the space surrounding the nucleus
what is the missing word- ...
velocity is vector quantity but speed is scalor quantity . why ?
speed speed scalar quantity is the rate of at which an object covers distance on the other hand velocity is a vector quantity it is direction aware.velocity is the rate at which the position changes.the average velocity is the displacement or position change Per time ratio.so velocity is a vector quantity but speed is a scalar quantity
A person drops an egg onto a carpet, and the egg doesn't break. Then she drops the egg onto a tile floor and it breaks. Which floor most likely had a greater amount of force, and a shorter collision time?
Answer: The tile floor.
Explanation:
We can think of this as follows:
By the second Newton's law, we know that:
F = m*a
force is equal to mass times acceleration.
Now, as the egg hits the ground, we can think that there is a force that is applied in a very short period of time.
(similar to the case of a bat hitting a baseball)
Ok, the total energy of the impact will be the same for any surface in which the egg falls.
But suppose that the egg falls in a carpet, in this case, the carpet has a kinda large collision time (the time that the force is applied to the egg), this means that we will have a smaller force, acting for a long period of time. Now if the egg falls on something harder, like the tile floor, the collision time will be a lot shorter, then the force must be a lot stronger to compensate, this force is so large, that breaks the shell of the egg.
the tile floor is then the correct answer.
A 70 kg astronaut throws a 5 kg ball with a velocity of 20 m/s east. What is the velocity of the astronaut?
Answer:
[tex]V_a =1.4285m/s[/tex]
Explanation:
From the question we are told that
70 kg astronaut
5 kg ball
A velocity of 20 m/s east
Generally with Law of conservation of momentum in place for a body in space
initial and final momentum must be equal
Therefore
[tex]M_b*V_b=M_a*V_a[/tex]
[tex]M_b=Mass of ball \\V_b=Ball velocity \\M_a= Mass of astronaut \\V_a= Astronaut velocity[/tex]
Mathematically solving for[tex]V_a[/tex]
[tex]V_a =\frac{5*20}{70}[/tex]
[tex]V_a =1.4285m/s[/tex]
Therefore the Astronauts velocity relative to his mass is given to be
[tex]V_a =1.4285m/s[/tex]
The velocity of the astronaut is 1.43 m/s.
From Newton's third law of motion,
To get the velocity of the astronaut, we use the formula below.
Formula:
MV = mv.................... Equation 1Where:
M = mass of the astronautV = Velocity of the astronautm = mass of the ballv = velocity of the ball.make V the subject of the equation
V = mv/M................. Equation 2From the question,
Given:
m = 5 kgv = 20 m/sM = 70 kgSubstitute these values into equation 2.
V = 5(20)/70V = 1.43 m/s.Hence, the velocity of the astronaut is 1.43 m/s.
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balance chemical equation NaNO3=>NaNO2+O2
The graph shows how the vertical velocity of a parachutist changes from the moment the parachutist jumps from the aircraft until landing on the ground. Using the idea of forces, explain why the parachutist reaches a terminal velocity and why opening the parachute reduces the terminal velocity.
Answer:
once the parachute is opened, the air resistance overwhelms the downward force of gravity. The net force and the acceleration on the falling skydiver is upward. ... The skydiver thus slows down. As the speed decreases, the amount of air resistance also decreases until once more the skydiver reaches a terminal velocity.
Explanation:
As the parachute is opened the air and due to the downward force of gravity the resource is upwards hence the skydiver falls slowly.
Who is a parachutist?A parachutist is one who uses a parachute when making a skydive. Once the parachute is opened the air offers some resistance and due to the downward force of gravity.
The net force and force of acceleration are on the skydiver and a, as a result, he falls slowly. As the speed gets decreased the amount of air resistance will also decrease.
Find out more information about the parachutist
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Sound waves are:
O Longitudinal Waves
O Transverse Waves
i need help with this question, i’ll mark as Brainliest!!
Answer:
The given Device is a :
SOLENOID.Since at the left corner, The MFL (Magnetic field lines) are entering the solenoid OR terminating at this end, This end turns out to be the SOUTH POLE.
According to the arrows, The current is always in the direction of the magnetic field. So, The current is leaving the Solenoid at the top right corner.
[tex]\rule[225]{225}{2}[/tex]
Hope this helped!
~AH1807Answer:
The name of the device is Solenoid. Left end represents South Pole. The current ( I ) is leaving the wire coil at the top right corner.
Explanation:
Hope you understand....
How much work is done by a 120N force applied to a box that moves 5m?
Answer:
600J
Explanation:
w=f×s
=120×5
600J
therefore the work by a force applied to a box that moves 5m is 600J
A 115 kg anvil is 85.0 m above the Coyote. How much gravitational
potential energy does it have?
Answer:
[tex]\boxed {\boxed {\sf 95,795 \ Joules}}[/tex]
Explanation:
Gravitational potential energy is found using the following formula.
[tex]E_p=m*g*h[/tex]
where m is the mass, g is the gravitational acceleration, and h is the height.
1. Define Variables
We know the anvil's mass is 115 kilograms and it's 85.0 meters above the coyote. Assuming this is on Earth, the acceleration due to gravity is 9.8 m/s²
[tex]m=115 \ kg \\h= 85.0 \ m \\g= 9.8 \ m.s^2[/tex]
2. Calculate Potential Energy
Substitute the values into the formula.
[tex]E_p=(115 \ kg)*(9.8 \ m/s^2)*(85.0 \ m)[/tex]
Multiply the first two numbers together.
[tex]E_p=1127 \ kg*m/s^2*(85.0 \ m)[/tex]
Multiply again.
[tex]E_p=95795 \ kg*m^2/s^2[/tex]
1 kilogram square meter per square second is equal to Joule. Therefore, our answer of 95795 kg*m²/s² is equal to 95795 J[tex]E_p=95795 \ J[/tex]
The anvil has 95,795 Joules of gravitational potential energy.
Suppose that two objects attract each other with a gravitational force of 16 units. If the mass of both objects was doubled, and if the distance between the objects was doubled, then what would be the new force of attraction between the two objects?
Answer:
Distance, such that displacement over time is taken into account doesn't change regardless of the length in x meters or mass in kg So the force will remain constant given 16 unitsThe new force of attraction between the two objects will be remain the same.
What is the gravitational law?The gravitational law states that the gravitation force is the ratio of the product of the masses and the square of the distance between them.
Let the masses be m and M and the distance between them is r. Then the force is given as,
F = GmM / r²
Suppose that two objects attract each other with a gravitational force of 16 units.
F = 16
GmM / r² = 16 units
If the mass of both objects was doubled, and if the distance between the objects was doubled. Then we have
F' = G(2m)*(2M) / (2r)²
F' = 4GmM / 4r²
F' = GmM / r²
F' = 16 units
The new force of attraction between the two objects will be remain the same.
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If you pluck a guitar string hard the sound waves it gives off will have __________ amplitudes.
small
large
Answer:
large
Explanation:
the harder you pluck the louder it gets
If you pluck the guitar string hard, the sound waves it gives off will have larger amplitudes
What will be the amplitudes of the waves?
We know that, for soundwaves, the amplitude is related to the intensity of the sound.
If you pluck the guitar string hard, you will notice that the intensity of the sound increases. So we can conclude that the amplitude of the soundwaves will be larger than if you plucked the guitar string softer.
Then the complete statement would be:
"The sound waves it gives off will have larger amplitudes."
If you want to learn more about waves:
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