At t = 0, a particle is at rest at origin. Its acceleration is 2 rn/ s² for the first 3s and -2 m / s² for next 3s. Plot the acceleration versus time and velocity versus time graph.

2

(a)

Prove that the horizontal range is same when angle of projection is less than 45^o by the same value.

2

(a)

Hatrick and Peterson were good friends. They went to a international trade fair at Pragati Maidan. Peterson saw a shop, where people were firing at balloons. He also asked the shopkeeper for a gun. Peterson fired three shots but none of the shots hit the target and he was qiute  confused. Hatrick was watching Peterson. He told Peterson to fire at the balloon by taking aim just above the balloon. Peterson listened to the advice of Hatrick and then he successfully hit all the balloons.
Hatrick asked Peterson to take aim just above the balloon. Why?

2

(a)

Can a flight of a bird, an example of composition of vectors. Why?

2

(a)

A person driving a car suddenly applies the brakes on seeing a child on the road ahead. If he is not wearing seat belt, he falls forward and hits his head against the steering wheel. Why ?

2

(a)

Explain how a cat is able to land on its feet after a fall taking the advantage of principle of conservation of angular momentum?

2

(a)

Does the change in gravitational potential energy of a body between two given points depends upon the nature of path followed, why?

2

(a)

How does tea in a thermo flask remain hot for a long time?

2

(a)

What are the basic requirements of a cooking utensils in respect of specific heat, thermal conductivity and coefficient of expansion?

2

(a)

Under what condition, an ideal Carnot engine has 100% efficiency?

2

(a)