Physics Test 15...

Four similar particles of mass m are orbiting in a circle of radius r is the same direction and same speed because of their mutual gravitational attractive force as shown in the figure. Speed of a particle is given by

A particle moves with a velocity  horizontally under the action of constant force  The instantaneous power supplied to the particle is :

The potential energy of a long spring when stretched by  2 cm is U. If the spring is stretched by  8 cm, potential energy stored in it will be :

A constant torque of   100 N m turns a wheel of moment of inertia 300 kg m² about an axis passing through its centre. Starting from rest, its angular velocity after  3 s is :-

The ratio of radius of gyration of a solid sphere of mass M and radius R about its own axis to the radius of gyration of the thin hollow sphere of same mass and radius about its axis is :-

An energy of 484 J is spent in increasing the speed of a flywheel from 60 rpm to 360 rpm. The moment of inertia of the flywheel is :

The angular acceleration of a body, moving along the circumference of a circle, is :

An electric lift with a maximum load of 2000 kg (lift + passengers) is moving up with a constant speed of 1.5 ms⁻¹. The frictional force opposing the motion is 3000 N. The minimum power delivered by the motor to the lift in watts is : (g = 10 ms⁻²)

The escape velocity of a body on the earth surface is 11.2 km/s. If the same body is projected upward with velocity 22.4 km/s, the velocity of this body at infinite distance from the centre of the earth will be:

If R is the radius of the earth and g is the acceleration due to gravity on the earth surface. Then the mean density of the earth will be :