Physics Unit-3 Test

For a small θ, angular displacement is quantity

• Scalar   

• Neither scalar nor vector

• Vector    

• None

In circular motion, if the angular velocity and angular acceleration becomes parallel, then the motion becomes:

• Slower  

• Constant

• Faster

• Both ‘A’ and ‘C’

A child riding on a large merry-go-round, travels a distance of 3000m in a circle of diameter 40m. The total angle through which child revolves is:

• 50 rad

• 75 rad

• 150 rad

• 314 rad

A body moves in a circle with increasing angular velocity. At time t= 6sec, the angular velocity is 27rad/s. What is the radius of circle made by the body where linear velocity is 81cm/s?

• 6cm 

• 9cm

• 3cm

• 7cm

A particle of mass m is moving in a horizontal circle of radius R with a uniform speed. When it moves to a point diametrically opposite then

• K.E. changes by mv² /4   

• Momentum does not change

• Momentum changes by -2 mv  

• K.E. changes by mv²

A particle of mass 2 kg is moving along a circular path of radius 1 m. if its angular speed is 2π rad s^–1, the centripetal force on it is:

• 4π N   

• 8π N

• 4π⁴ N  

• 8π² N

In circular motion, the radius vector

• Changes in direction but has a fixed magnitude

• Has constant magnitude and direction

• Changes in magnitude only

• Changes in magnitude as well as direction

The angular displacement covered by a body in the following graph is

• 40 rev

• 20 rev

• 30 rad 

• 40 rad

A car is moving with high velocity when it has a turn. A force acts on it outwardly because of

• Gravitational force 

• Centrifugal force

• Centripetal force

• All of these

All particles of a rigid body rotating about a fixed axis may not have same

• Angular displacement

• Speed

• Direction of angular velocity

• Axis of rotation