A force of 7N acts on an object. The displacement is 8m in the direction of force. What is the work done?
24 J
56 J
54 J
64 J
At the start of a freely falling object its kinetic energy is zero. Why ?
Because its velocity is zero
Because mass has no effect at that height
The body is at a height
All the above
Unit of power is
Watt
Joule
Newton
Pascal
Unit of work is
m/s
N
'Stone at a height'- which type of energy is related to this situation?
Kinetic energy
Potential energy
Mechanical energy
Electrical energy
Which of the following is the correct expression for potential energy of an object?
P E = mgh
P E = 1/2 m v2
P E = 2m g h
P E = mg/h
A compressed spring possesses
Elastic potential energy
Magnetic energy
What is the velocity of body of mass 100 g having a K.E. of 20 J?
2 m s-1
20 m s-1
40 m s-1
400 m/s
The energy used in households, industries and commercial establishments are usually expressed in
Joules
W
KWh
None of these.
When we increase the speed of an object, it kinetic energy
Also increases
Decreases
Does not change
First increases then decreases