Terminal Velocity (GCSE Physics)

Terminal Velocity

Acceleration due to Gravity

• Gravity affects all objects on Earth. Gravity is a strong force that affects object on the Earth, or close to the surface of the Earth. This force stops us from floating into space.
• Gravity causes acceleration. The force of gravity causes objects to accelerate towards the surface of the Earth. When an object falls freely under gravity, it experiences an acceleration of 9.8m/s².

Terminal Velocity

If an object has reached ‘terminal velocity’, this means it has reached a constant velocity. The forces on the object are balanced at this point.

We will now explore how a ball falling through fluid reaches terminal velocity. A fluid is referred to either a gas or liquid.

1. A ball is dropped into a fluid filled tube.
2. The weight of the ball is acting downwards, making the ball fall through the fluid very quickly.
3. As the ball accelerates, the fluid will oppose the motion. The fluid exerts a frictional force on the ball, making it more difficult for the ball to fall through the tube.
4. The frictional force gets larger and larger, making the ball accelerate less and less.
5. Eventually, the frictional force acting on the ball will become equal to the weight of the ball. At this point, the ball will not accelerate – instead, it will fall at a constant velocity.
6. The ball has now reached terminal velocity.