# Physics

1.A student moves a box of books down the hall
by pulling on a rope attached to the box. The
student pulls with a force of 181 N at an angle
of 20.8◦ above the horizontal. The box has a
mass of 40.3 kg, and μk between the box and
the floor is 0.29.
The acceleration of gravity is 9.81 m/s2 .
Find the acceleration of the box.

2.Now the student moves the box up a ramp
(with the same coefficient of friction) inclined
at 10.3◦ with the horizontal.
b) If the box starts from rest at the bottom
of the ramp and is pulled at an angle of 20.8◦
with respect to the incline and with the same
181 N force, what is the acceleration up the
ramp?
Answer in units of m/s2.

1. 👍
2. 👎
3. 👁
1. 1. Break the pulling force in to a vertical and horizontal component. The vertical component subtracts from the normal weight. So figure friction based on that.

Net horizontal force=m*a
horizonalPulling-friction= ma
sove force.

2. Again, break the pulling into a normal component and a parallel(plane) component.
the normal force will be mg*cosTeta-normalofPullingcomponent.
Friction= mu*normal force above.
Component of gravity down the plane, mgSinTheta..

Net up force=ma
ParallelPulling-friction-gravitydownplane=ma
solve for a

1. 👍
2. 👎
👤
bobpursley
2. Fx = 181 cos 20.8

normal force = m g - 181 sin 20.8
friction force =.29(mg-181 sin 20.8)

ma= 181cos 20.8-.29(mg-181 sin 20.8)
divide by m to get a

now you do the second one the same way

1. 👍
2. 👎

## Similar Questions

1. ### Physics

A horizontal rope is tied to a 45.0kg box on frictionless ice. What is the tension in the rope if: A) The box is at rest? B) The box moves at a steady vx = 4.40m/s ? C) The box vx = 4.40m/s and ax = 4.60m/s2 ?

2. ### physics

A student pulls on a rope attached to a box of books and moves the box down the hall. The student pulls with a force of 182N at an angle of 25° above the horizontal. The box has a mass of 35kg and &mu k between the box and the

3. ### physics

a girl is using a rope to pull a box that weighs 300N across a level surface with constant velocity. the rope makes an angle of 30 degree above the horizontal and the tension in the rope is 100N. What is the normal force of the

4. ### physics

A clerk moves a box of cans down an aisle by pulling on a strap attached to the box. The clerk pulls with a force of 173.0 N at an angle of 31° with the horizontal. The box has a mass of 40 kg, and the coefficient of kinetic

1. ### Physics

A student decides to move a box of books into her dormitory room by pulling on a rope attached to the box. She pulls with a force of 130 N at an angle of 30.0° above the horizontal. The box has a mass of 24.0 kg, and the

2. ### physics

a box with mass 20kg rests on a frictionless ramp with a 15degree slope. a mover pulls up on a rope attached to the box to pull it up the incline. if the rope makes a 40 degree angle with the horizontal, what's the smallest force

3. ### Physics 11

A single wave pulse is sent along a thick rope that's tied to a thin rope, which in turn is attached to a wall. Reflection of the wave will occur at both points A (where the thick rope is attached to the thin rope) & point B

4. ### Physics

A rope pulls on a metal box at an angle of 60.0° with a force of 255 N. The box moves horizontally for 15.0 m. How much work was done on the box? 1910 J 3310 J 255 J 3830 J

1. ### Physics

Beth, a construction worker, attempts to pull a stake out of the ground by pulling on a rope that is attached to the stake. The rope makes an angle of 44.8 ◦ with the horizontal. If Beth exerts a force of 146.8 N on the rope,

2. ### Phyiscs

A wooden box with a mass of 10.0kg rests on a ramp that is inclined at angle of 25 degrees to the horizontal. A rope attached to the box runs parallel to the ramp and then passes over a frictionless pulley. A bucket with a mass of

3. ### Physics

At the beginning of a new school term, a student moves a box of books by attaching a rope to the box and pulling with a force of F = 84.4 N at an angle of 64degrees. The acceleration of gravity is 9.8 m/s/s. The box of books has a

4. ### physics

A 73 kg crate is dragged across a floor by pulling on a rope attached to the crate and inclined 15° above the horizontal. (a) If the coefficient of static friction is 0.52, what minimum force magnitude is required from the rope