Motion on a rough inclined plane

In summary, the car is moving up a 10 degree inclined plane with a velocity of 10m/s. The coefficient of friction is 0.5 and the mass is 10kg. The car brakes and the distance it takes to stop is 7.65m. The net force acting on the car is the combined force of friction and weight, which results in a negative acceleration of -6.53m/s2. There is no upward force from the engine since the car is braking.
  • #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?
 
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  • #2
Since both force components are acting to slow the car down, should you be subtracting or adding them?
 
  • #3
scottdave said:
Since both force components are acting to slow the car down, should you be subtracting or adding them?

I guess I can either go for -(F1+F2) or -F1-F2 . I applied the second one
 
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  • #4
Taylan said:
I guess I can either go for -(F1+F2) or -F1-F2 . I applied the second one
OK, I missed the minus sign before the 0.5, the first time I looked at it. So you had it correct.
 
  • #5
Alright thanks a lot! so there isn't any force acting upwards by the engine since the car is braking right? like although the car is moving upwards, there are only forces that are acting downwards to be considered which are; friction and mg ?
 
  • #6
Taylan said:
Alright thanks a lot! so there isn't any force acting upwards by the engine since the car is braking right? like although the car is moving upwards, there are only forces that are acting downwards to be considered which are; friction and mg ?
Yes.
 

Related to Motion on a rough inclined plane

What is motion on a rough inclined plane?

Motion on a rough inclined plane refers to the movement of an object on a surface that is not completely smooth, and is tilted at an angle.

What factors affect motion on a rough inclined plane?

The factors that affect motion on a rough inclined plane are the angle of inclination, the coefficient of friction between the object and the surface, and the mass of the object.

How does the angle of inclination affect motion on a rough inclined plane?

The steeper the angle of inclination, the greater the force of gravity pulling the object down the plane, and the more difficult it is for the object to move up the plane.

What is the coefficient of friction and how does it affect motion on a rough inclined plane?

The coefficient of friction is a measure of the resistance between two surfaces in contact. A higher coefficient of friction means there is more resistance, making it harder for the object to move on the rough inclined plane.

What is the relationship between mass and motion on a rough inclined plane?

The greater the mass of the object, the more force is needed to move it up the rough inclined plane. This is because the weight of the object is directly proportional to its mass.

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