Question

A car is travelling at 30m/s and decelerates [with normal car brakes, no trick] at 5m/s/s for 10 s. What is the car's final speed *

A) zero
B) -50m/s
C) -20m/s
D) Not possible to tell
show your full work

Answer 1

B. -20 m/s

Step-by-step explanation:

Given the following data:

Initial velocity = 30 m/s

Acceleration = 5 m/s²

Deceleration = -5 m/s² (deceleration is the negative of acceleration)

Time = 10 seconds

To find the final velocity, we would use the first equation of motion;

`V = U + at`

Where;

V is the final velocity.

U is the initial velocity.

a is the acceleration.

t is the time measured in seconds.

Substituting into the formula, we have;

`V = 30 + (-5)*10`

`V = 30 - 50`

Final velocity, V = -20 m/s