# Force and Simple Dynamics: Dropped Tennis Ball

• Naeem
In summary, we have discussed the scenario of a 0.3 kg tennis ball being dropped from a height of 3.6 m onto a hard floor. Using the equation |v| = sqrt(2*9.81*3.6), we can determine the speed of the ball at the instant of contact with the floor to be approximately 8.4 m/s. We also established that the force acting on the ball while in contact with the floor is equal to |f| = N. To find the time over which the force acts in bringing the ball to rest, we can use the equation W = 0.006m*F, where W is the work done by the force and F is the force applied

#### Naeem

A 0.3 kg tennis ball is dropped from rest at a height of 3.6 m onto a hard floor.
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a) What is the speed of the ball at the instant of contact with the floor?
|v| = m/s *
sqrt( 2*9.81*3.6) OK

HELP: This is just a problem in one-dimensional kinematics with constant acceleration. What is the acceleration of the ball while it is in the air?

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A flash photograph shows that the ball is compressed a maximum of 0.6 cm when it strikes the floor.
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b) Assuming that the acceleration of the ball is constant during its contact with the floor, what force does the floor exert on the ball?
|f| = N

HELP: Again, this is a problem in one-dimensional kinematics with constant acceleration. What is the acceleration of the ball when it is in contact with the floor?

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c) Over what time does the force act in bringing the ball to rest?
D t = s

Request some guidance as how to proceed with part b and c.

Thanks,

What is the only force acting on the ball,while in the air.What is the force acting on the ball,while in contact with the ground?

What it the definition of average force?

Daniel.

Force due to gravity while in air , and on contact the balls acceleration.

Ft = mv

know m , v ... but don't know time

I know part c. once I find part b.

You know the kinetic energy of the ball when it is about to hit the ground.

You know that this energy was countered by the ground with a constant force that lasted x = 0.6cm.

You can find the force :)

Naeem said:
HELP: This is just a problem in one-dimensional kinematics with constant acceleration. What is the acceleration of the ball while it is in the air?

Well, the force responsible for the moton is gravity, so the acceleration is g

A flash photograph shows that the ball is compressed a maximum of 0.6 cm when it strikes the floor.

$$W = E_k^{END} - E_k^{BEGINNING}$$

W is work and in this case equal to 0.6*F and the change in kinetic energy is just the transferred kinetic energy when the ball hits the gorund (this is easy to calculate)...Solve this equation for F. the question really is : do you understand what this formula means physically ? Do you know what is happening ?

c) Over what time does the force act in bringing the ball to rest?

You can find this yourself, like you said

marlon

W is work and in this case equal to 0.6*F and the change in kinetic energy is just the transferred kinetic energy when the ball hits the gorund

Careful, 0.6*F isn't the correct equation. The ball was compressed 0.6cm, so 0.006m*F.

whozum said:
Careful, 0.6*F isn't the correct equation. The ball was compressed 0.6cm, so 0.006m*F.

Thanks for the correction whozum

marlon

## 1. How does the force of gravity affect a dropped tennis ball?

The force of gravity causes the tennis ball to accelerate towards the ground, increasing its velocity until it reaches its maximum speed.

## 2. Why does a dropped tennis ball bounce back up?

When the tennis ball hits the ground, it compresses and stores some of the energy from the impact. This energy is then released, causing the ball to bounce back up.

## 3. Does the height from which a tennis ball is dropped affect its bounce?

Yes, the higher the drop, the greater the potential energy the ball has. This means it will have a higher bounce than if it were dropped from a lower height.

## 4. How does air resistance affect the motion of a dropped tennis ball?

Air resistance, or drag, acts against the motion of the ball and can slightly decrease its speed and bounce height. However, for a small and dense object like a tennis ball, the effect of air resistance is minimal.

## 5. Can you calculate the force of impact when a tennis ball is dropped?

Yes, the force of impact can be calculated using the formula F = m x a, where F is the force, m is the mass of the ball, and a is the acceleration due to gravity (9.8 m/s²). By measuring the height of the drop and the time it takes for the ball to hit the ground, the acceleration can be determined and the force of impact can be calculated.