An electric train is moving with a velocity of $120 \, km \, h^{-1}$. How much distance will it cover in $30 \, s$ (in $, km$)?

What is meant by free fall? Two bodies,one of mass $1\,g$ and other of mass $1\,kg$,are dropped from the same height in a vacuum. Compare the two time intervals in which the two bodies will hit the ground.

Name the physical quantity which corresponds to the rate of change of momentum.

Define 'average speed'. An object moves with a uniform speed of $10\, m s^{-1}$ for $5\, s$ and then with a uniform speed of $5\, m s^{-1}$ for $10\, s$. Find its average speed.

$(a)$ Which type of motion is represented by the velocity-time graph shown below?
$(b)$ Name the physical quantity which can be calculated by the area of rectangle $OABC$.
$(c)$ What does the straight line $AB$ represent?

State whether the following statement is true or false:
Acceleration is defined as the rate of change of velocity.