4.1.1.2 Changes in Energy

Question 1

Work done:

Answer 1

the energy transferred when a force moves an object over a distance

Question 2

How do you calculate work done?

Answer 2

W = Fs
Work done(J) = Force(N) x distance moved in the direction of the force(m)

Question 3

How do you calculate the kinetic energy of a moving object:

Answer 3

Calculating the kinetic energy of a moving object:
KE = ½ mv²
Kinetic energy (J) = ½ x mass(kg) x velocity (m/s)

Question 4

How do you calculate the amount of gravitational potential energy gained by an object raised above ground level?

Answer 4

PE = mgh

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

Question 5

How do you calculate the amount of elastic potential energy stored in a stretch spring?

Answer 5

Elastic potential energy (E) = 0.5 x spring constant (N/m) x extension ² (m)
EE = ½ ke²

Question 6

What is work done (elastic potential wise)?

Answer 6

When a spring is stretched or compressed

Question 7

Work done =

Answer 7

elastic potential energy (as long as the elastic limit is not exceeded)

Question 8

What is the kinetic energy of a moving body directly proportional to?

Answer 8

the square of its speed

Question 9

What happens when there is an energy transfer of [elastic potential energy ——→ (mechanical pathway) gravitational potential energy] with an 100% efficient rate?

Answer 9

EE = EP