Question

A car moves from a position 50 m south of the library to a new position 250
m north of the library. This movement takes 15 seconds. What is the velocity
of the car?
O
O
O
O
A. 20 m/s north
B. 20 m/s south
C. 13 m/s south
D. 13 m/s north

Answer 1

Answer:

A. 20 m/s north

Explanation:

The velocity of the car can be  calculated as:

$v=\frac{d}{t}$

where

d is the displacement

t is the time interval

Taking north as positive direction, the initial position of the car is

$r_i = -50 m$ (south)

while the final position is

$r_f = +250 m$ (north)

So, the displacement is

$d=r_f -r_i = +250-(-50)=+300 m$ (north)

The time interval for the motion is

t = 15 s

So, the velocity of the car is

$v=\frac{+300}{15}=+20 m/s$ (north)