# Physics

A wooden block of mass 9 kg is at rest on an inclined plane sloped at an angle theta from the horizontal. The block is located 5 m from the bottom of the plane.
A) Find the frictional force for theta = 20
B)If the angle is increased slowly the block starts sliding at an angle theta = 30. What is the coefficient of static friction?
C) If the block slides to the bottom in 2 s, what is the coefficient of kinetic friction?

1. 0
2. 0
3. 21
1. M*g = 9 * 9.8 = 88.2 N. = Wt. of block.

A. Fp = 88.2*sn20= 30.2 N. = Force
parallel to the in.cline.

Fn = 88.2*Cos20 = 82.9 N. = Normal or force perpendicular to the incline.

Fs = u*Fn = u*82.9.

Fp-Fs = M*a. 30.2-82.9u = M*0 = 0, 82.9u = 30.2, u = 0.364 = Static coefficient of friction.

Fs = u*Fn = 0.364 * 82.9 = 30.2 N. = Force of static friction.

B. Fp = 88.2*sin30 = 44.1 N.

Fn = 88.2*Cos30 = 76.4 N.

Fs = u*Fn = u*76.4.

Fp-Fs = M*a.
44.1 - 76 .4u = M*0 = 0, u = 0.577.

1. 0
2. 0
posted by Henry

## Similar Questions

1. ### Physics

A wooden block of mass m = 9 kg starts from rest on an inclined plane sloped at an angle θ from the horizontal. The block is originally located 5m from the bottom of the plane. If the block, undergoing constant acceleration down

asked by Mike on February 3, 2013
2. ### Physics

A wooden block of mass m = 2.3 kg starts from rest on an inclined plane sloped at an angle 26 degrees from the horizontal. The block is originally located 1.9 m from the bottom of the plane. Assume the inclined plane is friction

asked by Sydney on February 26, 2014
3. ### physics

A centreate block mass 25kg is placed on a wooden plant inclined at an angle 32 dergree to the horizontal calculate the force parallel to the inclined plane that would keep the block rest .If the cofficient of fricition between

asked by awoyele tobi on November 8, 2016
4. ### Physics

A 0.9-kg block (mass m) and a second block (mass M) are both initially at rest on a frictionless inclined plane. Mass M rests against a spring that has a force constant of 12.2 kN/m. The distance d along the plane between the two

asked by Anonymous on November 9, 2014
5. ### physics

A 2.0-kg wooden block slides down an inclined plane 1.0 m high and 3.0 m long. The block starts from rest at the top of the plane. The coefficient of kinetic friction between the block and plane is 0.35. What is the speed of the

asked by angel on August 1, 2011

Two blocks are connected by a string over a frictionless, massless pulley such that one is resting on an inclined plane and the other is hanging over the top edge of the plane. The inclined plane is inclined at an angle of 37

asked by Jared on November 20, 2013
7. ### physics

Two blocks are connected by a string over a frictionless, massless pulley such that one is resting on an inclined plane and the other is hanging over the top edge of the plane. The inclined plane is inclined at an angle of 37

asked by Haff on November 20, 2013
8. ### Physics

A block P of mass 2.75 kg is lying on a rough inclined plane of angle è=0.87 radians. Block P is attached via a model string that passes over a model pulley to a second block Q of unknown mass M kg hanging vertically. The

asked by Anonymous on March 6, 2012
9. ### Physics

A 2.5 kg block sits on an inclined plane with a 30 degree inclination. A light cord attached to the block passes up over a light frictionless pulley at the top of the plane and is tied to a second 2.5 kg mass freely hanging

asked by Margaret on October 11, 2013
10. ### science

A steel block weighing 12N is pulled up an incline plane 20° above the horizontal by a constant force of 7.35 N which makes an angle of 10° above the inclined plane. The block stars from rest and is pulled 2.0m along the

asked by John on June 20, 2018

More Similar Questions