# Thread: Kinematics of a Particle

1. ## Kinematics of a Particle

4). A particle of mass m kg is at rest on a rough plane inclined at an angle above the horizontal. Force X N acts on the particle up the greatest slope of the plane, as shown in the diagram. Find the magnitude and direction of the frictional force when:

a). X = 10, m = 1
b). X = 10, m = 2

I don't really have any idea what to do. The answer for part 1 is 5.1N, and part 2 is 0.2N. Can you help?

2. Originally Posted by Viral
4). A particle of mass m kg is at rest on a rough plane inclined at an angle above the horizontal. Force X N acts on the particle up the greatest slope of the plane, as shown in the diagram. Find the magnitude and direction of the frictional force when:

a). X = 10, m = 1
b). X = 10, m = 2

I don't really have any idea what to do. The answer for part 1 is 5.1N, and part 2 is 0.2N. Can you help?

the system is in equilibrium ... forces down the incline = force up the incline

$f_s + mg\sin{\theta} = x$

3. Thanks, I've got it .