Question

A car is initially traveling due north at $23m/s$. Find the velocity of the car after $4s$ if its acceleration is $2m/s^2$ due south. (in m/s) :

• A. $10$ due south
  
• B. $15$ due north
  
• C. $14$ due north
  
• D. $12$ due south
  

Answer 1

Answer: (B)

$15$ due north

Initial speed of car $u=23m/s$ (due North)
Time taken $t=4s$
Acceleration $a=-2m/s^2$ (due North)
Applying $Ist$ $eqn$ of motion,
$v=u+at$
$v=23-2\times 4$
$⟹$ $v=15m/s$ (due North)