Jane drops a football from the roof onto the ground below. The ball weighs 0.8kg and the distance the ball falls is 5m. Assuming there are no external forces acting on the ball, what speed will the ball be travelling at just before it hits the ground?
As the ball falls from a height to the floor, the gravitational potential energy stored in the ball will be converted to kinetic energy.The gravitational potential energy of the ball can be calculated using:gpe = mgh : m =0.8kg, g=9.8N/kg, h=5m so gpe = 0.8 x 9.8 x 5 = 39.2JKinetic energy can be calculated using: eK = 0.5 x m x v^2 . We can rearrange this to get v = SqRt (( 2 x eK )/ m).eK = 39.2J, m=0.8kg, so v = SqRt ((2 x 39.2)/0.8) = 9.899 m/s. To 2sf this is 9.9m/s
KO
Related Physics GCSE answers
All answers ▸Describe the forces acting on an object on earth falling through the air, and how they change from when the object is first released into the air leading to terminal velocity.
Do batteries contain current, which comes out when they are in a circuit?
How do current and voltage vary in series and parallel circuits, respectively?
Draw a graph depicting a skydivers speed against time when jumping from a plane, until he deploys his parachute, explaining the logic of your answer through the forces applicable to the body.