PHYSICS
1. Derive expression for force of attraction
between two bodies and then define
gravitational constant.
2. A stone is dropped from the top of a 40 m-high
tower. Calculate its speed after 2 s. Also, find the
speed with which the stone strikes the ground.
3. Show that the weight of an object on the moon
is 1/16 of its weight on the earth?
4. Suppose the gravity of the earth suddenly
becomes zero, then in which direction will the
the moon begins to move if no other celestial body
affects it?
5. When does an object show weightlessness?
6. A person holds a bundle of hay over his head
for 30 minutes and gets tired. Has he done some
work or not? justify your answer.
7. Distinguish between work, energy, and power.
State the SI units for each of these quantities.
8. When an arrow is shot from its bow, it has
kinetic energy. From where does it get the
kinetic energy?
9.(a)A boy of mass 50 kg climbs up a vertical
height of 100 m. Calculate the amount of
potential energy he gains.
(b)A block of mass 5 kg is lying bn a frictionless
table. A force of 20 N is applied to it for 10
seconds. Calculate its kinetic energy.
10. Name the transformation of energy involved
in the following cases :
(a) When a body is thrown upwards.
(b) When a body falls from the top of a hill.
(c) When coal burns.
(d) When a gas burns.
(e) When water falls from a height.