Question

The velocity versus time graph of a body is as shown in the figure below. What is the distance travelled and average velocity of the body ?

• A. $100\text{m}$ and $2.5\text{m/s}$
• B. $40\text{m}$ and $1\text{m/s}$
• C. $100\text{m}$ and $0\text{m/s}$
• D. $40\text{m}$ and $0\text{m/s}$

Answer 1

The correct option is C $100\text{m}$ and $0\text{m/s}$

Area $A_1=\frac{1}{2}\times 20\times 5=50$
$A_2=\frac{1}{2}\times 20\times (-5)=-50$
The area under the velocity-time curve gives the distance travelled by the body.
Distance $=|A_1|+|A_2|=50+50$
Distance travelled $=100\text{m}$
However displacement $=A_1+A_2=50-50=0$
Since, $\text{Average velocity}=\frac{\text{Displacement}}{\text{Time taken}}$
$\Rightarrow \text{Average velocity}=0$
Hence the correct option is (c).