Question

A car is initially moving at 20 m/s east and a little while later it is moving at 10 m/s north. Which of the following best describes the orientation of the average acceleration during this time interval?
a.northeast

b.northwest

c.west

d.north of west

Answer 1

Answer:d

Explanation:

Given

First car is moving  towards east with velocity 20 m/s

$\vec{v_1}=20\hat{i}$

then it turns towards north then velocity is  

$\vec{v_2}=10\hat{j}$

suppose car takes t sec to change its path so average acceleration is given by

$a=\frac{v_2-v_1}{t}$

$a=\frac{1}{t}(10\hat{j}-20\hat{i})$

So average  acceleration is towards North of west.