Calculate the velocity of the bob of a simple pendulum at its mean position if it is able to rise to a vertical height of 10 cm. [g = 9.8 m/s²]

2

(a)

Can a body have without momentum? If yes, then explain how they are related with each other?

2

(a)

A spring balance reads forces in Newtons. The scale is 20 cm long and read from 0 to 60 N. Find potential energy of spring when the scale reads 20 N.

2

(a)

A steel spring of spring constant 150 N/m is compressed from its natural position through a mud wall 1m thick, the speed of bullet drops to 100m/s. Calculate the average resistance of the wall. Neglect friction of air.

2

(a)

A trolley of mass 300 kg carrying a sand bag of 25 Kg is moving uniformly with a speed of 27km/h on a frictionless track. After a while , sand starts leaking out of a whole on the floor of the trolley at the rate of 0.052 kg^-1.What is the speed of the trolley after the entire sand bag is empty?

2

(a)

A vertical spring with constant 200 N/m has a light platform on its top. When a 500 g mass is kept on the platform spring compresses 2.5 cm.Mass is now pushed down 7.50 cm further and released. How far above later position will the mass fly? (g = 10 ms^-1).

2

(a)

What is the significance of the -ve sign in W = - mgd?

2

(a)

What is the elastic potential energy stored in a spring?

2

(a)

Why is the work done by centripetal force zero?

2

(a)

Give an example of negative work.

2

(a)

What happens when two identical objects moving in mutually opposite directions suffer all elastic collision?

2

(a)

What is a headon collision?

2

(a)

The momentum of an object is doubled. How does its K.E. change?

2

(a)

If mechanical work is done on a body, will its kinetic energy increase or decrease?

2

(a)

A bullet of mass 20 g is moving with a speed of 150 m S^-1. It strikes a target and is brought to rest after piercing 10 cm into it. Calculate the average force of resistance offered by the target.

2

(a)