Practice MCQ Questions and answers on Physics-GK

The rate of change of displacement of an object (displacement over elapsed time) is velocity. Velocity is a vector since it has both magnitude (called speed) and direction.

When a ball is thrown vertically upwards, several physical quantities change during its motion. However, one quantity that remains constant during its motion is energy.

As the ball rises, its kinetic energy decreases while its potential energy increases. When it reaches its highest point and starts to fall back down, the potential energy decreases, and the kinetic energy increases. The total mechanical energy (the sum of kinetic and potential energy) remains constant as long as no external forces (like air resistance) are acting on the ball.

The other options are not constant during the motion:
Option B: Displacement changes continuously as the ball moves up and then comes back down.
Option C: Velocity changes as the ball moves upward (velocity decreases) and then downward (velocity increases).
Option D: Acceleration is also not constant. It changes due to the gravitational force, causing deceleration as the ball rises and acceleration as it falls.

So, the correct answer is Option A: Energy, which remains constant during the motion of a ball thrown vertically upwards, provided there are no external forces affecting it.

For a body moving with non-uniform velocity and uniform acceleration, Displacement – Time graph is non-linear.

When man throws the stone upward with speed u and downward with speed u, the initial velocity (from the cliff) will be the same. Hence, this will result in equal final velocity.
Hence the ratio is 1:1.

Scalar Quantities are physical quantities which have magnitude only and no direction.

At poles, value of g is maximum. So, there is no effect of rotation of earth.

If a body is accelerated, then the velocity will also get increased.

During uniform motion of an object along a straight line, the velocity remains constant with time.

The slope of a velocity graph represents the acceleration of the object. So, the value of the slope at a particular time represents the acceleration of the object at that instant.

The slope of a velocity graph represents the acceleration of the object. So, the value of the slope at a particular time represents the acceleration of the object at that instant.