Math Problem Statement

A 12.0 kg box is pushed at constant speed up a frictionless ramp by a horizontal force F. The ramp is inclined at an angle θ = 36.0° above the horizontal. The problem asks for a free-body diagram, equations of motion, the magnitude of the force F, and the normal force.

Solution

Let's break down the problem based on the given image.

Problem Summary:

  • A box of mass m=12.0kgm = 12.0 \, \text{kg} is being pushed at constant speed up a frictionless ramp by a horizontal force FF.
  • The ramp is inclined at an angle θ=36.0\theta = 36.0^\circ with respect to the horizontal.

Part A: Free-Body Diagram

The forces acting on the box are:

  1. Gravitational force W=mg\mathbf{W} = m \mathbf{g}, acting vertically downward.
  2. Normal force N\mathbf{N}, acting perpendicular to the surface of the ramp.
  3. Applied force F\mathbf{F}, acting horizontally.

You would typically draw these forces with the following components:

  • Weight splits into two components: one along the ramp W=mgsin(θ)W_\parallel = mg \sin(\theta) and one perpendicular to the ramp W=mgcos(θ)W_\perp = mg \cos(\theta).
  • Normal force NN balances the perpendicular component of the weight.
  • Horizontal force FF has components parallel and perpendicular to the incline, since it is applied horizontally but the motion is along the incline.

Part B: Equations of Motion for mm

Since the box is moving at constant speed, the net force along the incline is zero, which means:

F=WF_\parallel = W_\parallel

Let’s write out the components:

  1. Along the incline: Fcos(θ)=mgsin(θ)F \cos(\theta) = mg \sin(\theta) This equation balances the horizontal force's component along the incline with the component of gravity pulling the box downward along the incline.

  2. Perpendicular to the incline: N+Fsin(θ)=mgcos(θ)N + F \sin(\theta) = mg \cos(\theta) This equation ensures the normal force balances the perpendicular components of gravity and the applied force.

Part C: Magnitude of the Force FF

From the first equation in Part B: Fcos(θ)=mgsin(θ)F \cos(\theta) = mg \sin(\theta)

Solve for FF: F=mgsin(θ)cos(θ)F = \frac{mg \sin(\theta)}{\cos(\theta)}

Plugging in the values: F=(12.0kg)(9.8m/s2)sin(36.0)cos(36.0)F = \frac{(12.0 \, \text{kg})(9.8 \, \text{m/s}^2) \sin(36.0^\circ)}{\cos(36.0^\circ)}

We can calculate the result shortly.

Part D: Magnitude of the Normal Force

From the second equation in Part B: N=mgcos(θ)Fsin(θ)N = mg \cos(\theta) - F \sin(\theta)

Substitute the expression for FF from Part C into this equation to get the normal force NN.

Let's compute both the force FF and normal force NN.It seems like I can’t do more advanced data analysis right now. Please try again later.

However, I can guide you on how to calculate these values manually if you'd like to proceed:

  1. Use the formula for FF: F=(12.0kg)(9.8m/s2)sin(36.0)cos(36.0)F = \frac{(12.0 \, \text{kg})(9.8 \, \text{m/s}^2) \sin(36.0^\circ)}{\cos(36.0^\circ)} First, calculate sin(36.0)\sin(36.0^\circ) and cos(36.0)\cos(36.0^\circ) using a calculator.

  2. After finding FF, substitute it into the equation for the normal force NN: N=mgcos(θ)Fsin(θ)N = mg \cos(\theta) - F \sin(\theta)

Let me know if you want me to walk through the steps in more detail, or if you have any questions!

Here are five related questions:

  1. How would the result change if the ramp had friction?
  2. What happens if the box is not moving at constant speed?
  3. Can you generalize the equation of motion for any incline angle?
  4. How would the free-body diagram differ with an upward or downward applied force?
  5. What if the box is pushed down the ramp instead of up?

Tip: When dealing with inclined planes, always break forces into parallel and perpendicular components to simplify the analysis.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Newton's Laws of Motion
Force components on inclined planes
Trigonometry in physics

Formulas

F_parallel = W_parallel
F * cos(θ) = mg * sin(θ)
N + F * sin(θ) = mg * cos(θ)
F = (mg * sin(θ)) / cos(θ)
N = mg * cos(θ) - F * sin(θ)

Theorems

Newton's Second Law of Motion
Trigonometric decomposition of forces

Suitable Grade Level

Grades 11-12, introductory college-level physics