11.

In the motion of a rocket, physical quantity which is conserved is

• angular momentum

• linear momentum

• force

• work

An aeroplane is flying horizontally with a velocity of 600 km/h and at a height of 1960 m. When it is vertically above a point A on the ground a bomb is released from it. The bomb strikes the ground at point B. The distance AB is

• 1200 m

• 0.33 km

• 3.33 km

• 33 km

A 10 kg object collides with stationary 5 kg object and after collision they stick together and move forward with velocity 4 ms^-1. What is the velocity with which the 10 kg object hit the second one ?

• 4 ms^-1

• 6 ms^-1

• 10 ms^-1

• 12 ms^-1

When a force is applied on a moving body, its motion is retarded. Then the work done is

• positive

• negative

• zero

• positive and negative

Physical independence of force is a consequence of

• third law of motion

• second law of motion

• first law of motion

• all of these laws

The kinetic energy of a body becomes four times its initial value. The new momentum will be

• same as the initial value

• twice the initial value

• thrice the initial value

• four times the initial value

An ice cart of mass 60 kg rests on a horizontal snow patch with coefficient of static friction $\frac{1}{3}$. Assuming that there is no vertical acceleration, find the magnitude of the maximum horizontal force required to move the ice cart. (g = 9.8 ms^-2)

• 100 N

• 110 N

• 196 N

• 206 N

Moment of a couple is called

• impulse

• couple

• torque

• angular momentum

A cyclist is moving in a circular track of radius 80 m with a velocity v = 36 km/h. He has to lean from the vertical approximately through an angle : (Take g = 10 ms^-2)

• ${\tan }^{-1} \left(4\right)$

• ${\tan }^{-1} \left(\frac{1}{3}\right)$

• ${\tan }^{-1} \left(\frac{1}{8}\right)$

• ${\tan }^{-1} \left(2\right)$

An athlete throws a discus from rest to a final angular velocity of 15 rad/s in 0.270 s before releasing it. During acceleration, discus moves a circular arc of radius 0.810 m. Acceleration of discus before it is released is

• 45 ms^-2

• 182 ms^-2

• 187 ms^-2

• 192 ms^-2