Question

A velocity-time graph of freely falling body is:
A) A straight line with positive slope to the time axis.
B) A straight line with negative slope to the time axis.
C) A straight line parallel to the time axis.
D) A straight line parallel to the acceleration axis.

Answer 1

Hint: When we drop a body it will be in free fall motion under gravity. In this motion, a constant acceleration is applied on the body due to Earth’s gravitational force. This acceleration is known as acceleration due to gravity.

Complete step by step answer:
A body can be said to be in free fall when it is dropped from a certain height and is allowed to fall under the effect of gravity. The moment a body is dropped, a force of gravity due to Earth pulls it towards its centre.
We know from Newton's laws that whenever a body is acted upon by a force, there must be a certain value of acceleration with the body. This acceleration in case of gravitation is known to be acceleration due to gravity.
A constant acceleration means that there must be a constant increase in the value of velocity of the object with respect to the time period.
If we plot a velocity-time graph of a body in free fall, due to a constant acceleration on the body, a straight line with positive slope to the time axis would be observed. The slope will be positive as there is a constant acceleration with time.
This can be shown in the given below diagram.


Thus, from the given options, option A is the correct option.

Note: Remember that a constant acceleration acts on the free falling body. The acceleration on the body is constant; this doesn’t mean that the graph will be a straight line parallel to the time axis. A constant acceleration means increase in velocity. Thus, option A and C shouldn’t be confused.