A brass ball is hanging from a stiff cotton thread. Draw a neat labelled diagram showing the forces acting on the brass ball and cotton thread.

2.

The distance between two bodies is doubled. How is the magnitude of the gravitational force between them affected?

Why is a jack screw provided with a long arm?

If the power of a motor is 100 kW, at what speed can it raise a load of 50,000 N?

Which class of lever will always have MA > 1 and why? 

Define heat capacity and state its SI unit.

Why is the base of a cooking pan generally made thick?

A solid of mass 50 g at 150°C is placed in 100 g of water at 11°C, when the final temperature recorded is 20°C. Find the specific heat capacity of the solid. (specific heat capacity of water = 4.2 J/g°C)

How is the refractive index of a material related to: 
(i) real and apparent depth?
(ii) velocity of light in vacuum or air and the velocity of light in a given medium?

State the conditions required for total internal reflection of light to take place.