Question

6) If a car goes from 20 miles per hour to 10 miles per hour in 5 seconds, find its acceleration.

a.2 miles per hour per second
b.5 miles per hour per second
c.-2 miles per hour per second
d.10 miles per hour per second

Answer 1

ANSWER IS C

The car is accelerating at -2 miles per hour per second. Although the units seem odd, it is distance/time2, which is acceptable for acceleration. a=

v

t

=10-20/5=-2.

Answer 2

Answer;

C.-2 miles per hour per second

Step-by-step explanation;

Acceleration = change in velocity / time

Acceleration = (final velocity - initial velocity )/time

Acceleration = (v - u)/t

Given: u = 20 miles per hour, v = 10 miles per hour

t = 5 seconds

Acceleration = (10 - 20)/5

Acceleration = -10/5

Acceleration = -2 miles per hour per second