Question

A 1150 kg sports car accelerates from rest to 80 km/h in 7.4s. What is the average power delivered by the engine? Express your answer using two significant figures.

Answer 1

First, let's convert the final velocity from km/h to m/s:


`image`

Next, we'll calculate the acceleration using the formula
`image`

Now, we can calculate the force using
F=ma, where the mass m = 1150 kg.


`F=1150kg×3.0m/s^(2)`=
3450N
 
The next step is to calculate the work done using
`image`


`image`

Now, we'll use the formula for power:

`image`,where
t=7.4s

`image`

Rounding to two significant figures, the average power delivered by the engine is approximately

`image`
So, the average power delivered by the engine is around 39 kW.