Download Potential and Kinetic Energy Questions (In the following questions

Potential and Kinetic Energy Questions
(In the following questions, assume g = 10m/s2, and that friction can be ignored).
GPE = mgh
KE = mv2
2
Work = Force x distance
1a.
An object has a mass of 6kg. Calculate it's potential energy:i)
6m above the ground.
ii)
12m above the ground.
GPE = 360 J
GPE = 720 J
b.
At what height above the ground will its potential energy be 420J?
h= 7 meters
2.
A stone has 160J of potential energy. What will be it's potential energy if it's height above the ground is
halved?
PE = 80 J
3.
An object of mass 8kg is travelling with a velocity of 6m/s.
i)
What is it's kinetic energy?
ii)
What will be it's kinetic energy if it's velocity is doubled?
i)
144 J
ii) 576 J
4.
A stone has a mass of 30kg. Dropped form a cliff top, the stone strikes the sea below with a velocity of
15m/s.
i)
What is the kinetic energy of the stone as it is about to hit the sea?
ii)
What was it's potential energy before it was dropped?
iii)
From what height was the stone dropped?
i)
5.
ii) PE= 3375 J
iii) h = 11.25 meters
A car of mass 5kg is pulled along a flat bench by a force of 4N. When the car has travelled 2m,
calculate:i)
How much work has been done on it.
ii)
How much kinetic energy it has gained.
i)
6.
KE = 3375 J
W= 8 J
ii) KE = 8 J
B
The ball in the diagram has a mass of 3kg. 100J of work were done
in moving the ball up the smooth slope from D to A.
i)
What is the potential energy of the ball at A?
D it's fall?
ii)
If the ball falls, what is it's potential energy at B, the mid point of
iii)
What is it's kinetic energy at B?
iv)
If the ball were to roll back down the slope rather then fall, what would be it's kinetic energy as it
reached D?
i)
PE = 100 J
ii) PE = 50 J
iii)
KE = 50 J
iv) KE = 100 J
Hard Question
7.
A
A ball of mass 1.5kg has 200J of kinetic energy. What is the velocity of the ball?
V= 16.33 m/s