Two racing cars of masses \(m_1\) and \(m_2\) are moving in circles of radii \(r_1\) and \(r_2\) respectively. Their speeds are such that each makes a complete circle in the same duration of time \(t\). The ratio of the angular speed of the first to the second car is:

1.	\(m_1:m_2\)	2.	\(r_1:r_2\)
3.	\(1:1\)	4.	\(m_1r_1:m_2r_2\)

If a particle moves in a circle describing equal angles in equal times, its velocity vector:

1. remains constant.

2. changes in magnitude.

3. changes in direction.

4. changes both in magnitude and direction.

A motorcyclist going round in a circular track at a constant speed has:

1. constant linear velocity.

2. constant acceleration.

3. constant angular velocity.

4. constant force.

A particle P is moving in a circle of radius ‘a’ with a uniform speed v. C is the centre of the circle and AB is a diameter. When passing through B the angular velocity of P about A and C are in the ratio 

1. 1 : 1

2. 1 : 2

3. 2 : 1

4. 4 : 1

A particle moves with constant angular velocity in a circle. During the motion its:

Two bodies of mass 10 kg and 5 kg moving in concentric orbits of radii R and r such that their periods are the same. Then the ratio between their centripetal acceleration is 

1. R/r

2. r/R

3. R²/r²

4. r²/R²

A particle is moving in a horizontal circle with constant speed. It has constant 

1. Velocity

2. Acceleration

3. Kinetic energy

4. Displacement

The angular speed of a flywheel making 120 revolutions/minute is: 

1. $2\pi rad/s$

2. $4{\pi }^{2}rad/s$

3. $\pi rad/s$

4. $4\pi rad/s$

Certain neutron stars are believed to be rotating at about 1 rev/sec. If such a star has a radius of 20 km, the acceleration of an object on the equator of the star will be 

1. $20\times {10}^{8}m/{\sec }^2$

2. $8\times {10}^{5}m/{\sec }^2$

3. $120\times {10}^{5}m/{\sec }^2$

4. $4\times {10}^{8}m/{\sec }^2$

An electric fan has blades of length 30 cm as measured from the axis of rotation. If the fan is rotating at 1200 r.p.m, the acceleration of a point on the tip of the blade is about

1. 1600 m/sec²

2. 4740 m/sec²

3. 2370 m/sec²

4. 5055 m/sec²