• Support PF! Buy your school textbooks, materials and every day products via PF Here!

Mass on a moving wedge

  • Thread starter bigevil
  • Start date
1. Homework Statement

2eofudg.jpg


This is a frictionless system with the wedge on a frictionless horizontal surface. When the system is released, the horizontal wedge (mass M) with diagonal angle theta moves to the left with constant acceleration a. What is it?

I hope I'm right when I say this is not a very easy question, because I spent ages on it but I'm still not sure what the answer is. Can someone please help me check the answer?

2. Homework Equations

The mass (=m) does not leave the wedge. Taking the perpendicular component of the wedge's acceleration,

[tex]ma sin \theta = mg cos \theta - N[/tex] where N is the normal reaction force between the wedge and the mass, directed perpendicular to the plane.

Applying Newton's second law, the horizontal acceleration on the wedge is solely created by the normal force. Therefore [tex]Ma = N sin \theta[/tex]. Then applying algebra,

[tex]a = \frac{mg sin\theta cos\theta}{M + m {sin}^2 \theta}[/tex].
 
I think you have your answer. No values have been given for any of the variables so the best you can get is an expression for a.

Edit: I just worked it out myself and I got the same expression for a as you
 
Last edited:
All right... thanks :)
 

Related Threads for: Mass on a moving wedge

Replies
2
Views
6K
  • Posted
Replies
2
Views
1K
Replies
3
Views
3K
  • Posted
Replies
5
Views
2K
  • Posted
Replies
5
Views
9K

Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving
Top