A car moves at a speed of 20ms-1 on a banked track and describes an arc of a circle of radius . The angle of banking is (take g = 10 ms-2)
25°
60°
45°
30°
When a body is projected vertically up from the ground with certain velocity, its potential energy and kinetic energy at a point A are in the ratio 2 : 3. If the same body is projected with double the previous velocity, then at the same point A the ratio of its potential energy to kinetic energy is
9 : 1
2 : 9
1 : 9
9 : 2
A spring with force constant k is initially stretched by x1. If it is further stretched by x2, then the increase in its potential energy is
B.
According to the question, in the first condition
In the second condition,
Increment in the potential energy
A force Fx acts on a particle such that its position x changes as shown in the figure.
The work done by the particle as it moves from x = 0 to 20 m is
37.5 J
10 J
45 J
22.5 J
Two objects P and Q initially at rest move towards each other under mutual force of attraction. At the instant when the velocity of P is v and that of Q is 2v, the velocity of centre of mass of the system is
v
3v
zero
1.5 v
A body rolls down an inclined plane . If its kinetic energy of rotation is 40% of its kinetic energy of translation motion, then the body is
hollow cylinder
ring
solid disc
solid sphere
A circular disc A and a ring B have same mass and same radius. If they are rotated with the same angular speed about their own axis, then
A has less moment of inertia than B
A has less rotational kinetic energy than B
A and B have the same angular momentum
A has greater angular momentum than B
Angular momentum of the Earth revolving around the Sun in a circular orbit of radius R is proportional to
R
R2
R1/3
A body of mass m is released from a height equal to the radius R of the Earth. The velocity with which it will strike the Earth's surface is
A satellite revolves around the Earth of radius R in a circular orbit of radius 3R. The percentage increase in energy required to lift it to an orbit of radius 5R is
10 %
20 %
30 %
40 %