Question

A particle moving on straight line whose velocity-time graph is shown in the figure. The average speed from $t=0$ to $t=6s$ is $v=\frac{15}{n}{ms}^{-1}$. Find the value of $n$.

• A. $2$
• B. $3$
• C. $5$
• D. $1$

Answer 1

The correct option is A $2$

Area of graph for $0\le t\le 5s$, $A_1=\frac{1}{2}(3+5)\times 10=40m$

Area of graph for $5\le t\le 6s$, $A_2=\frac{1}{2}\times 10\times 1=5m$

Total distance covered in 6 seconds $d=A_1+A_2=40+5=45m$

Total time $t=6s$

Average speed $V_{avg}=\frac{d}{t}=\frac{45}{6}=\frac{15}{2}m/s$

$⟹n=2$