Analyzing Forces on a Moving System: Newton's Second Law in Action

Join the discussion
Ask a follow-up here, or get your own question answered by working scientists, mathematicians and engineers — people, not an autocomplete.
Real named experts · corrections over time · the nuance an AI answer skips
1 reply · 2K views
mathmannn
Messages
15
Reaction score
0

Homework Statement



I attached the photo of the question that has everything.

Homework Equations



[itex]F=ma[/itex]

The Attempt at a Solution



So I found the total mass of the system 50+35 = 85. Since we are given the force in the x-direction I used [itex]\frac{70}{85} = a = .8235[/itex]. The weight of the cylinder is 50*g = 490 N, and weight of the cart is 35*g = 343 N. But I don't know where to go from there. I know that the reaction at A will be larger than at B because the "pulling" force will cause the cylinder to push more on the left side of the cart.. But I don't know how to relate anything to get useful equations.
 

Attachments

  • Screen Shot 2012-02-03 at 9.31.55 PM.png
    Screen Shot 2012-02-03 at 9.31.55 PM.png
    6.6 KB · Views: 535
Physics news on Phys.org
Your acceleration calc in the x directon is correct. The cylinder must also move at that same acceleration in the x direction. What is the cylinder's acceleration in the y direction? You must draw a free body diagram of the cylinder and identify the forces acting on the cylinder in the x and y directions. In what direction do the normal forces act? Then use Newton's laws in the x and y direction.