An astronaut experiences weightlessness in a space satellite. It is because

• the gravitational force is small at that location in space

• the gravitational force is large at that location in space

• the astronaut experiences no gravity

• the gravitational force is infinitely large at that location in space

2.

The displacement of a particle moving along x-axis with respect to time t is x = at + bt² − ct³. The dimensions of c are

• [T^-3]

• [LT^-2]

• [LT^-3]

• [LT³]

A particle moving along a straight line covers half of the distance with a speed of 3 ms^-1. The other half of the distance is covered in two equal time intervals with speed of 4.5 ms^-1 and 7.5 ms^-1. The average speed of the particle (in ms^-1) is

• 5.0

• 5.5

• 5.8

• 4.0

Two cars started moving with initial velocities v and 2 v. For the same deceleration, their respective stopping distances are in the ratio

• 1 : 1

• 1 : 2

• 1 : 4

• 2 : 1

The distances traversed during equal intervals of time by a freely falling body from rest are in the ratio

• 1 : 3 : 5 : 7 ....

• 2 : 4 : 6 : 8 .....

• 1 : 4 : 9 : 25 .....

• 1 : 9 : 25 : 49 .....

In the entire path of a projectile, the quantity that remains unchanged is

• vertical component of velocity

• horizontal component of velocity

• kinetic energy

• potential energy

The sum of magnitudes of two forces acting at a point is 16 N and their resultant $8\sqrt{3}$ N is at 90° with the force of smaller magnitude. The two forces (in N) are

• 11, 5

• 9, 7

• 2, 14

• 4, 12

Among the following, the vector quantity is

• pressure

• gravitation potential

• stress

• impulse

A block of mass 10 kg is moving horizontally with a speed of 1.5 ms^-1 on a smooth plane. If a constant vertical force 10 N acts on it, the displacement of the block from the point of application of the force at the end of 4 s is

• 5 m

• 20 m

• 12 m

• 10 m

A block of weight 4 kg is resting on a smooth horizontal plane. If it is struck by a jet of water at the rate of 2 kgs^-1 and at the speed of 10 ms^-1, then the initial acceleration of the block is

• 15 ms^-2

• 10 ms^-2

• 5 ms^-2

• 1 ms^-2