Choose the correct options:
1. The work done in lifting a brick of mass 2kg through a height of 5m above ground will be
A) 2.5J
B) 10J
C) 50J
D) 100J
2. The work done will be zero when the angle b/w the force and the distance is
A) 45֯
B) 60 ֯
C) 90֯
D) 180֯
3. Which one of the following converts light energies into electrical energy?
A) Electric bulb B) Electric generator
C) Photocell
D) Electric cell
Short Questions:
i.
ii.
iii.
iv.
v.
A force of 100N acts on a body of mass 20kg. The force accelerates the body from rest
until it attains a velocity of 20ms-1. Through what distance the force acts?
Why are fossil fuels called a non-renewable form of energy?
How energy is converted from one form to another form of energy. Explain with the help
of the rain process.
How can you find the efficiency of a system?
A cyclist does 12J of useful work while pedalling his bike from every 100j of food
energy that he takes. What is his efficiency?
Long Questions:
i.
ii.
Define kinetic energy. And derive the expression for kinetic energy?
Calculates the power of a pump that can lift 200kg of water through a height of 6m in
10s?