Math Problem Statement

What is the total work WF1��1 done on the block by the applied force F⃗ 1�→1 as the block moves a distance L� up the incline?

Express your answer in terms of any or all of the variables μ�, m�, g�, θ�, L�, and F1�1.

Solution

To find the total work WF1W_{F_1} done on the block by the applied force F1\vec{F_1} as it moves a distance LL up the incline, we consider the force components acting on the block.

  1. Work Done by the Applied Force: The work done by the applied force F1\vec{F_1} is given by: WF1=F1Lcos(α)W_{F_1} = F_1 \cdot L \cdot \cos(\alpha) where α\alpha is the angle between the applied force and the direction of motion. If F1\vec{F_1} is parallel to the incline, α=0\alpha = 0 and thus cos(0)=1\cos(0) = 1.

    Hence, WF1=F1LW_{F_1} = F_1 \cdot L

  2. Components of Forces:

    • The gravitational force acting down the incline is mgsin(θ)mg \sin(\theta).
    • The frictional force acting opposite to the direction of motion is Ffriction=μmgcos(θ)F_{\text{friction}} = \mu mg \cos(\theta).
  3. Total Work Against Gravity and Friction: The work done against gravity and friction while moving up the incline is: Wgravity=mgsin(θ)LW_{\text{gravity}} = mg \sin(\theta) \cdot L Wfriction=μmgcos(θ)LW_{\text{friction}} = \mu mg \cos(\theta) \cdot L

  4. Total Work Done: Thus, the net work done on the block considering these forces is: Wnet=WF1WgravityWfrictionW_{\text{net}} = W_{F_1} - W_{\text{gravity}} - W_{\text{friction}}

    Substituting values gives: WF1=F1L(mgsin(θ)+μmgcos(θ))LW_{F_1} = F_1 \cdot L - (mg \sin(\theta) + \mu mg \cos(\theta)) \cdot L

  5. Final Expression: WF1=L(F1mgsin(θ)μmgcos(θ))W_{F_1} = L \left( F_1 - mg \sin(\theta) - \mu mg \cos(\theta) \right)

This expression gives the total work done on the block by the applied force as it moves a distance LL up the incline.

Would you like more details on any part of this? Here are some related questions you might consider:

  1. How does the angle of the incline affect the work done?
  2. What happens to the work done if the friction coefficient changes?
  3. How do you calculate the acceleration of the block?
  4. What is the relationship between work and energy in this scenario?
  5. How would the work done change if the block moved down the incline instead?

Tip: Always ensure to resolve forces into components parallel and perpendicular to the motion for accurate work calculations.

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Math Problem Analysis

Mathematical Concepts

Physics
Work and Energy
Forces on Inclines

Formulas

W_{F_1} = F_1 \cdot L \cdot \cos(\alpha)
W_{\text{gravity}} = mg \sin(\theta) \cdot L
W_{\text{friction}} = \mu mg \cos(\theta) \cdot L
W_{\text{net}} = W_{F_1} - W_{\text{gravity}} - W_{\text{friction}}

Theorems

Work-Energy Theorem

Suitable Grade Level

Grades 11-12