Find the Kinetic Frictional Force on a 9kg Block on an Incline

In summary, a wooden block with a mass of 9 kg slides down an inclined plane at an angle of 30° with a constant acceleration. It starts from a distance of 5m from the bottom and reaches the bottom in 2 seconds. The normal force is calculated to be 88.2 N using F=ma. To find the frictional force, you need to use the kinematic equations to calculate the acceleration and then use that to find the force.
  • #1
wolves5
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A wooden block of mass m = 9 kg starts from rest on an inclined plane sloped at an angle q from the horizontal. The block is originally located 5m from the bottom of the plane. If the block, undergoing constant acceleration down the ramp, slides to the bottom in t = 2 s, and q = 30°, what is the magnitude of the kinetic frictional force on the block?

For this problem, the kinetic frictional force is = to (coefficient frictional force)(normal force). However, there is no coefficient frictional force in this problem. How do I get that? I calculated the normal force to be 88.2. I did F=ma. F=(9 kg) (9.81 m/s2), and got 88.2 N. How do I find the frictional force?
 
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  • #2
You have an object under uniform acceleration. Using kinematic equations, you should be able to calculate the magnitude of acceleration from the givens (remember you are given time, distance and initial velocity). After you have the acceleration, you should be able to get a force.
 

Related to Find the Kinetic Frictional Force on a 9kg Block on an Incline

1. What is kinetic frictional force?

Kinetic frictional force is a type of force that opposes the motion of an object when it is in motion.

2. How is kinetic frictional force calculated?

Kinetic frictional force is calculated by multiplying the coefficient of kinetic friction (μ) by the normal force (N) exerted on the object. The formula is Fk = μN.

3. What is the normal force?

The normal force is the perpendicular force exerted by a surface on an object in contact with it. It is equal in magnitude but opposite in direction to the force exerted by the object on the surface.

4. How do you find the coefficient of kinetic friction?

The coefficient of kinetic friction can be found by dividing the kinetic frictional force by the normal force. In other words, μ = Fk/N.

5. How does the mass of the object affect the kinetic frictional force?

The mass of the object does not directly affect the kinetic frictional force. However, a heavier object will have a greater normal force, which in turn will result in a greater kinetic frictional force. The coefficient of kinetic friction remains constant for a given combination of materials.

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