Question

A 2000 kg car starts from rest and coasts down from te top of 5m long driveway that is sloped at an angle of 20 degrees with the horizontal. If a constant 4000N frictional force resists the car's motion, find the speed of the car at the bottom of the driveway?

Answer 1

Answer:3.67 m/s

Step-by-step explanation:

Given

mass of car
`m=2000 kg`

Initial velocity
`u=0`

Length of track
`L=5 m`

inclination of driveway
`\theta =20^(\circ)`

Friction Force
`F=4000 N`

Sin component of weight accelerate the car while friction tries to oppose the car i.e.

`mg\sin \theta -F=ma_(net)`

`a_(net)=g\sin \theta -(F)/(m)`

`a_(net)=9.8\sin 20-2=1.35 m/s^2`

Using
`v^2-u^2=2 as`

`v=final\ velocity`

`v=√(2* 1.35* 5)`

`v=√(13.517)=3.67 m/s`