Question

A 2.1 ✕ 103-kg car starts from rest at the top of a 5.9-m-long driveway that is inclined at 19° with the horizontal. If an average friction force of 4.0 ✕ 103 N impedes the motion, find the speed of the car at the bottom of the driveway.

Answer 1

3.9 m/s

Step-by-step explanation:

We are given that

Mass of car,m=
`2.1* 10^3 kg`

Initial velocity,u=0

Distance,s=5.9 m

`\theta=19^(\circ)`

Average friction force,f=
`4.0* 10^3 N`

We have to find the speed of the car at the bottom of the driveway.

Net force,
`F_(net)=mgsin\theta-f=2.1* 10^3* 9.8sin19-4.0* 10^3`

Where
`g=9.8 m/s^2`

Acceleration,
`a=(F_(net))/(m)=(2.1* 10^3* 9.8sin19-4.0* 10^3)/(2.1* 10^3)`

`v=√(2as)`

`v=\sqrt{2* (2.1* 10^3* 9.8sin19-4.0* 10^3)/(2.1* 10^3)* 5.9}`

v=3.9 m/s