Practice MCQ Questions and answers on Physics-GK

A cricketer lowers his hands while taking a catch to decrease the rate of momentum. Cricketers increase the time by pulling their hand's backward with the ball while taking a catch. Linear momentum or translational momentum is the product of the mass and velocity of an object.

The unit of momentum is the product of the units of mass and velocity.

Both stones reach the ground at the same time. The initial speed is 0 for both stones, and the only acceleration working in that system would be g (Gravity acceleration). So, as the distance is the same, the final speed will be the same time. The only reason which could change this result is a difference in the shape of the stones. While they fall to the ground, they must “open” a way across the air. The shape of the falling object will decide the force needed to open that way. This is called the “Air resistance”. Depending on the shape of the object, the resistance force will be bigger or smaller. As this force works counter to g, the falling time will decrease. Between a feather and a plumb ball, the falling time will be the same in vacuum, but inside air, the resistance force for the feather has almost the same value than gravity, while for the ball, the resistance is very much weaker than gravity.

When a man jumps out of a moving train, his feet suddenly comes to rest on touching the ground. But, the upper part of the body continues to be in motion and has a tendency to move forward. That is why the person falls with his head forward.

An object at rest will remain at rest and an object in motion will remain in motion until and unless it is acted upon by an external force. This is Newton's first law of motion.

The attractive force that the celestial bodies exert on other masses by virtue of their total mass is called the force of gravity or gravitational force.

The ball is thrown in vertically upward direction and given that the train is moving up with a constant velocity. Therefore, the horizontal velocity of the train and ball are both same. And, the ball travels the same horizontal distance as that of the train. Therefore, the ball will come back into the hands of thrower.

The pole strength of each piece when a bar magnet is cut into two equal halves perpendicular to its length is the same as the pole strength of the original bar magnet. However, the magnetic moment of each piece is half the magnetic moment of the original bar magnet.

A permanent magnet can affect both magnets and electromagnets.

A freely suspended magnet remains horizontal at the magnet equator.