You want to push a 66-kg box up a 30° ramp. The coefficient of kinetic friction between the ramp and the box is 0.35. With what magnitude force parallel to the ramp should you push on the box so that it moves up the ramp at a constant speed?

Question

You want to push a 66-kg box up a 30° ramp. The coefficient of kinetic friction between the ramp and the box is 0.35. With what magnitude force parallel to the ramp should you push on the box so that it moves up the ramp at a constant speed?

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Physics - bobpursley, Thursday, February 16, 2012 at 5:04pm

You have to overcome friction and gravity

gravity down the plane:mg*SinTheta
friction: mg*mu*cosTheta

add them.

Physics - Anonymous, Thursday, February 16, 2012 at 5:15pm

Thanks

Physics - Anonymous, Thursday, February 16, 2012 at 7:25pm

I did that but it gives me wrong answer

Answer 1

To determine the magnitude of the force parallel to the ramp needed to push the box up the ramp at a constant speed, you need to consider the forces acting on the box.

1. Start by calculating the force of gravity acting on the box down the ramp. The force of gravity is given by the equation:

force_gravity = mass * acceleration_due_to_gravity

In this case, the mass of the box is 66 kg, and the acceleration due to gravity is 9.8 m/s^2.

2. Next, calculate the component of the force of gravity that acts parallel to the ramp. Use the equation:

force_gravity_parallel = force_gravity * sin(theta)

Theta represents the angle of the ramp, which is 30° in this case.

3. Calculate the force of kinetic friction acting on the box. The force of kinetic friction can be found using the equation:

force_friction = coefficient_of_friction * force_normal

The coefficient of kinetic friction is given as 0.35. To find the force normal (the normal force), use the equation:

force_normal = mass * acceleration_due_to_gravity * cos(theta)

4. Now, add up the forces acting on the box parallel to the ramp. The forces are the force of gravity parallel to the ramp and the force of kinetic friction. Use the equation:

force_total = force_gravity_parallel + force_friction

5. Finally, the magnitude of the force parallel to the ramp should be equal to the force_total calculated in step 4, as the applied force must be equal to the total opposing force for the box to move at a constant speed up the ramp.

Note: Make sure to use consistent units throughout the calculations (e.g., kilograms for mass, meters per second squared for acceleration, etc.)

By following these steps, you should be able to calculate the correct magnitude of the force parallel to the ramp required to move the box at a constant speed.