Question

Imagine you had a ball on top of a hill and you gave it a little push to get it to start rolling

downhill. As the ball rolls it does not roll faster or slower until it reaches the bottom of the
hill where it eventually comes to a stop.


1.1 Draw a labled free-body diagram of the ball, showing all forces acting on
the ball, before you pushed it at the top of the hill and when it came to a
stand still at the bottom (One diagram).
Draw it on a piece of paper (3 marks)


1.2 Draw a labled free-body diagram of the ball, showing all forces acting on
the ball, after you pushed it at the top of the hill. In other words whilst it was
in motion going down the hill at a constant velocity.
Draw it on a piece of paper,
(4 marks)

1.3 Draw what you think the slope of the hill looks like. Only draw a basic side
profile of the hill/slope.
Draw it on a piece of paper (2 marks)


1.4 What effect of forces was demonstrated by the experiment?

Answer 1

Answer: 1.1 Before the ball was pushed at the top of the hill and when it came to a standstill at the bottom, the following forces were acting on the ball:

- Gravitational force (labeled as "mg") acting downward towards the center of the Earth.

- Normal force (labeled as "N") acting upward perpendicular to the surface of the hill.

- Frictional force (labeled as "f") acting upward opposite to the direction of motion.

1.2 After the ball was pushed at the top of the hill and while it was in motion going down the hill at a constant velocity, the following forces were acting on the ball:

- Gravitational force (labeled as "mg") acting downward towards the center of the Earth.

- Normal force (labeled as "N") acting upward perpendicular to the surface of the hill.

- Frictional force (labeled as "f") acting upward opposite to the direction of motion.

Since the ball is moving at a constant velocity, the frictional force is equal in magnitude and opposite in direction to the gravitational force, balancing each other out. This is why the ball maintains a constant velocity without speeding up or slowing down.

1.3 The slope of the hill can be represented as a simple side profile. The hill would have an incline, with the height increasing as you move up and the slope getting steeper.

1.4 The experiment demonstrates the effect of forces in equilibrium. When the ball reaches a constant velocity going down the hill, the gravitational force pulling the ball downward is balanced by the frictional force acting upward. This balance of forces results in a net force of zero, allowing the ball to maintain a constant velocity without any acceleration.