Kinetic and gravitational potential energy - Topic 1

Question 1

What is gravitational potential energy?

Kinetic and gravitational potential energy

Answer 1

The energy store of an object due its height from the ground.

Question 2

What is the equation for calculating gravitational potential energy?

Kinetic and gravitational potential energy

Answer 2

Ep = mgh
Gravitational potential energy (J) = mass (kg) x gravitational field strength (N/kg) x height (m)

Question 3

What is kinetic energy?

Kinetic and gravitational potential energy

Answer 3

The energy store of a moving object. (kinetic is from a Greek work “kinesis” meaning motion)

Question 4

What is the equation for kinetic energy?

Kinetic and gravitational potential energy

Answer 4

Ek = 1/2mv2
Kinetic energy (J) = 1/2 x mass (kg) x velocity2 (m/s)

Question 5

Which energy store is empty when an object thrown upwards is at its maximum height?

Kinetic and gravitational potential energy

Answer 5

Kinetic energy (the object is temporarily stationary).

Question 6

When an object falls to the ground, when will ALL the energy in the gravitational store be shifted to the kinetic store?

Kinetic and gravitational potential energy

Answer 6

If there is a closed system, with no external forces (air resistance) acting on the object

Question 7

A penny dropped from a building has 21 J of gravitational potential energy. Before it hits the floor it has 18 J of kinetic energy. Why are these values of energy different?

Kinetic and gravitational potential energy

Answer 7

3 J of energy has been dissipated to the thermal store of the air due to air resistance.