Why are porcelain objects wrapped in paper or straw before packing for transportation ?

2

(a)

A passenger of mass 72.2 kg is riding in an elevator while standing on a platform scale. What does the scale read when the elevator cab is 
(i) descending with constant velocity
(ii) ascending with constant acceleration, 3.5 m/s²?

2

(a)

A force of 128 If acts on a mass of 490 g for 10 s. What velocity will it give to the mass ?

2

(a)

A body of mass 2 kg is being dragged with a uniform velocity of 2 ms ^-1 on a rough horizontal plane. The coefficient of friction between the body and the surface is 0.2. Calculate the amount of heat generated per second. Take  g =9.8 ms^-2 and J = 1.2Jcal^-1

2

(a)

Explain why passengers are thrown forward from their seats when a speeding bus stops suddenly,

2

(a)

Explain why a cricketer moves his hands backwards while holding a catch.

2

(a)

An athlete runs some distance before taking a jump. Explain why?

2

(a)

What is the angle between frictional force and instantaneous velocity of the body moving over a rough surface?

2

(a)

What is the apparent weight felt by a person in an elevator, when it is accelerating: (i) upward (ii) downward?

2

(a)

Which law of motion is involved in rocket propulsion?

2

(a)

What provides the centripetal force to a car taking a turn on a level road?

2

(a)

The linear momentum of the body can change only in the direction of applied force. Comment.

2

(a)

Name the forces which have shortest range and the longest range.

2

(a)

A stone, when thrown on a glass window, smashes the window pane to pieces. But a bullet fired from a gun passes through making a hole. Why?

2

(a)

Why are curved roads generally banked?

2

(a)