Question

A car advertisement states that a certain car can accelerate from rest to

40 km/hr in 5 sec. Find the car's average acceleration.

Answer 1

Refer to the attachment.

Answer 2

a = 2.22 [m/s^2]

Step-by-step explanation:

First we have to convert from kilometers per hour to meters per second

`40 [(km)/(h)]*[(1h)/(3600s)]*[(1000m)/(1km)] = 11.11 [m/s]`

We have to use the following kinematics equation:

`v_(f)= v_(i)+(a*t)`

where:

Vf = final velocity = 11.11 [m/s]

Vi = initial velocity = 0

a = acceleration [m/s^2]

t = time = 5 [s]

The initial speed is taken as zero, as the car starts from zero.

11.11 = 0 + (a*5)

a = 2.22 [m/s^2]