Question

An object starts from rest and accelerates uniformly in a straight line in the positive x direction. After 11 seconds, its speed is 70.0 m/s. What is the average velocity of the object during the first 11 seconds?

Answer 1

Answer:

$v_{avg}=35m/s$

Explanation:

To calculate the average velocity we must know the distance traveled and do $v_{avg}=\frac{d}{t}$. The distance traveled is $d=\frac{at^2}{2}$, so we need to calculate the acceleration, which, since it's uniform, is $a=\frac{\Delta v}{\Delta t}=\frac{v_f}{t}$. Putting all together:

$v_{avg}=\frac{d}{t}=\frac{at^2}{2t}=\frac{at}{2}=\frac{v_ft}{2t}=\frac{v_f}{2}=35m/s$