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 \(120\ \text{revolutions/minute }\)is: 

1. \(2 𝜋\ \text{𝑟𝑎𝑑/𝑠}\) $\mathrm{}$

2. \(4 𝜋^2\ \text{𝑟𝑎𝑑/𝑠}\)$\mathrm{}$

3. \(𝜋\ \text{𝑟𝑎𝑑/𝑠}\)$$

4. \(4 𝜋\ \text{𝑟𝑎𝑑/𝑠}\)$\mathrm{}$

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

1. \(20×10^8\ \text{m/s}^2\)

2. \(8×10^5\ \text{m/s}^2\)

3. \(120×10^5\ \text{m/s}^2\) $\mathrm{}$

4. \(4×10^8\ \text{m/s}^2\)$\mathrm{}$

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

1. \(1600\ \text{m/s}^2\)

2.  \(4740\ \text{m/s}^2\)

3. \(2370\ \text{m/s}^2\)

4. \(5055\ \text{m/s}^2\)

The angular speed of the second hand in a mechanical watch is:

1. \(\dfrac{\pi}{30}\ \text{rad/s}\) 

2. \(2\pi\ \text{rad/s}\)

3. \(\pi\ \text{rad/s}\)

4. \(\dfrac{60}{\pi}\ \text{rad/s}\)