# Kinetic and potential energy

### What should we know to be able to solve these exercises?

### Kinetical and potential exercises

Direct access to the Youtube channel (exercises 7 to 23)

### Energy - Exercise 07

A tennis ball is dropped from a height of 2 m. At what speed does it hit the ground?

### Energy - Exercise 08

A ball has a mass of 0'5 kg. Dropped from a cliff top, the ball hits the sea below at a speed of 10 m/s.

- What is the kinetic energy of the ball as it is about to hit the sea?
- What was the ball's gravitational potential energ before it was dropped?
- From what height was the ball dropped?

### Energy - Exercise 09

If we drop to the floor a stone which has a mass of 4 kg from a height of 4 m,

- What is its kinetic energy when it has fallen half-way to the ground?
- What is its speed when it reaches the floor?

### Energy - Exercise 10

Consider again the example of dropping a ball whose mass is a 0'2 kg. Calculate the gravitational energy lost by the ball upon falling 3 m.

### Energy - Exercise 11

Use conservation of energy to predict the speed of a dropped object that has fallen a distance of half a meter.

### Energy - Exercise 12

Imagine dropping a mass of 1.000 kg from a plane when it is at a height of 800 m. Find out its kinetic and potential energy:

- At the exact moment of dropping it.
- When the object has fallen 430 m.

### Energy - Exercise 13

Imagine dropping a stone whose mass is 10 kg. from a height of 500 m.

- Calculate its energy at the highest point. Which type is it?
- Calculate its kinetic energy when hits the floor.

### Energy - Exercise 14

Imagine dropping a stone whose mass is 5 kg from a height of 200 m.

- Calculate its potential energy at the highest point.
- Calculate its kinetic energy when it hits the floor.

### Energy - Exercise 15

Imagine dropping a mass from a plane flying at a speed of 900 km/h when it is at height of 3 km. Find out its speed when it hits the floor.

### Energy - Exercise 16

Imagine dropping a ball of 500 g from window situated 30 m above the floor. Find out:

- Its potential energy when it is dropped.
- Its kinetic energy when it hits the floor.
- Its speed when it hits the floor