Question

The position of the particle is given by $x=t^2+5t+2$ in $\text{m}$. The average speed of the particle in $6\text{sec}$ is

• A. $11\text{m/s}$
• B. $10\text{m/s}$
• C. $13\text{m/s}$
• D. $12\text{m/s}$

Answer 1

The correct option is A $11\text{m/s}$

Given, $x=t^2+5t+2$
We know that the average speed is given by $\frac{(x_f-x_i)}{t}$
So, at $t=0,x_i=0+0+2=2\text{m}$
and, at $t=6sec,x_f=6^2+5\times 6+2=68\text{m}$
Thus, average speed $=\frac{68-2}{6}=11\text{m/s}$