A body is at rest on the surface of the earth. Which of the following statement is correct?
No free is acting on the body
Only weight of the body acts on it.
Net downward force is equal to the net upward force.
None of the above statement is correct
A boy of mass 50 kg is standing on a weighing machine placed on the floor of a lift.The machine reads his weight in Newtons.What is the reading of the machine if the lift is moving upwards with a uniform speed of 10 m/sec2?
(g = 10 m/sec2 )
510 N
480 N
490 N
500 N
Two trains A and B are running in the same direction on parallel tracks such that A is faster than B.If packets of equal weight are exchanged between the two, then
A will be retarded but B will be accelerated
A will be accelerated but B will be retarded
there will not be any change in the velocity of A but B will be accelerated.
there will not be any change in the velocity of B,but A will be accelerated.
A lift is moving upward with increasing speed with acceleration 'a'.The apparent weight will be :
less than the actual weight
more than the actual weight and have a fixed value
more than the actual weight which increases as long as velocity increases
zero
Two balls of mass 1 kg and 2 kg respectively are connected to the two ends of the spring. The two balls are pressed together and placed on a smooth table. When released the lighter ball moves with acceleration of 2 ms-2. The acceleration of the heavier ball will be
4 ms-2
2 ms-2
1 ms-2
0.5 ms-2
Two blocks P and Q are released at the top of a rough inclined plane so that P slides along the plane and Q falls down freely. Which will have higher velocity on reaching the ground?
P
Q
Both will reach the ground with same velocity
It depends on the coefficient of friction
When a bullet of mass 5 kg is fired, the impulse on it is 200 Ns. If the mass of the gun is 10 kg, then the recoil velocity of the gun is
20 ms-1
2 ms-1
0.2 ms-1
0.02 ms-1
The product of force and velocity is called
impulse
torque
power
work
Kilowatt-hour is the unit of
energy
none of the above
Which of the following is a vector physical quantity?
Work
Kinetic energy
Moment of force
Potential energy
