1441. The Centripetal force for a car moving on a road is given by :
A. Friction due to tires *
B. Force of brakes
C. The driver of the car
D. Force by steering wheel
1442. If the earth were to rotate faster, than its present speed the weight of an object will :
A. It goes up at the equator but stays the same at the poles.
B. It goes down at the equator but stays the same at the poles. *
C. It stays the same at the decrease but goes down at the poles.
D. It stays the same at the equator but goes up at the poles.
1443. Centre of mass is a point :
A. Which is geometric centre of a body
B. At what distances are the particles identical?
C. Where the whole mass of the body is supposed to be centred *
D. Which is the origin of refernce frame
1444. What will be the duration of the day and night ( in hour ) if the diameter of the earth is suddenly reduced to half its original value, the mass remaining constant ?
B. 6 *
1445. A person standing on a rotating platform has his hands lowered. He suddenly outstretches his arms. The angular meomentum :
A. Becomes zero
D. Remains the same *
1446. A 500 kg car takes a round turn of radius 0 m with a velocity of 36 km/h . The centripetal force is :
A. 250 N
B. 750 N
C. 1000 N *
D. 1200 N
1447. Coin of radius R is beaten uniform to make a disc of radius 2R. Its moment of inertia :
B. Increases *
C. Remains the same
D. Decreases or increases depending on the actual value
1448. A cylinder cannot roll on :
A. A rough horizontal plane
B. A smooth horizontal plane
C. A rough inclined plane
D. A smooth inclined plane *
1449. For a body moving with constant speed in a horizontal circle, which of the following remains constant ?
B. Centripetal force
D. Kinetic energy *
1450. Angular momentum has the same unit as :
A. Impulse * distance *
B. Linear momentum * time
C. Work * frequency
D. Power * time