- #1

Taylan

- 52

- 1

## Homework Statement

A car is moving up a rough inclined plane/road of 10 degrees with a velocity of 10m/s. The coefficient of friction is equal to 0.5 and the mass of the car is 10kg. The car brakes. After what distance does the car stop?

## Homework Equations

F=ma

v^2=u^2+2as

u= initial velocity

v= final velocity

## The Attempt at a Solution

s=?

u= 10m/s

v= 0m/s

a= ?

a= net force/ mass

= [(-0,5 x 10kg x 9.81m/s2 x cos10) - 10kg(9.81m/s2)(sin10) ]/ 10kg = -6.53m/s2

and using v^2=u^2+2as , s is found to be 7.65m

What I am confused about is the net force for which I assumed to be:

(-0,5 x 10kg x 9.81m/s2 x cos10) - 10kg(9.81m/s2)(sin10)

So I just calculated -[ the weight of the car acting downwards + friction ( found by μR) ]. The car is actually moving upwards. But there is no force by the engine in upwards direction? So is the net force really acting downwards?