Acceleration due to gravity is g on the surface of the earth. Then the value of the acceleration due to gravity at a height of 32 km above earth's surface is (Assume radius of earth to be 6400 km)

• 0.99 g

• 0.8 g

• 1.01 g

• 0.9 g

The dimensions of kinetic energy is

• [M²L²T]

• [ML²T]

• [ML²T^-2]

• [ML²T^-1]

If the figure below represents a parabola, identify the physical quantities  representing Y and X for constant acceleration

• X = time, Y = velocity

• X = velocity, Y = time

• X = time, Y= displacement

• X = time, Y = acceleration

A ball which is at rest is dropped from a height h metre.  As it bounces off the floor its speed is 80% of what it was just before touching the ground. The ball will then rise to nearly a height

• 0.94 h

• 0.80 h

• 0.75 h

• 0.64 h

Two bodies of different masses are dropped from heights of 16 m and 25 m respectively. The ratio ofthe time taken by them to reach the ground is

• $\frac{25}{16}$

• $\frac{5}{4}$

• $\frac{4}{5}$

• $\frac{16}{25}$

The recoil velocity of a 4.0 kg rifle that shoots a 0.050 kg bullet at a speed of 280 ms^-1 is

• + 3.5 ms^-1

• − 3.5 ms^-1

• $- \sqrt{\left(3.5\right)} {\mathrm{ms}}^{-1}$

• $+ \sqrt{\left(3.5\right)} {\mathrm{ms}}^{-1}$

A man of height h walks in a straight path towards a lamp post of height H with uniform velocity u. Then the velocity of the edge of the shadow on the ground will be

• $\frac{\mathrm{hu}}{\left(\mathrm{H} - \mathrm{h}\right)}$

• $\frac{\mathrm{Hu}}{\left(\mathrm{H} + \mathrm{h}\right)}$

• $\frac{\left(\mathrm{H} - \mathrm{h}\right)}{\mathrm{Hu}}$

• $\frac{\left(\mathrm{H} + \mathrm{h}\right)}{\mathrm{Hu}}$

8.

A train of 150 m length is going towards north direction at a speed of 10 ms^-1 . A parrot flies at a ,speed of 5ms^-1 towards south direction parallel to the railway track. The time taken by the parrot to cross the train is equal to

• 12 s

• 8 s

• 15 s

• 10 s

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

• 333.3 km

• 3.33 km