Applied force on two blocks on a horizontal frictional plane

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Homework Help Overview

The discussion revolves around a physics problem involving two blocks connected by a string, being pulled across a rough horizontal surface. The problem includes parameters such as mass, applied force, angle, and friction coefficient, with a focus on determining the magnitude of the applied force given the acceleration of the blocks.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss drawing free body diagrams (FBD) and summing forces in both x and y directions. There are questions about the appropriate force to consider against friction for the block being pulled, and how to express the normal force.

Discussion Status

Some participants have provided guidance on analyzing forces and have attempted calculations for the normal force and tension in the string. There is ongoing exploration of how to correctly identify the forces acting on each block, particularly regarding the applied force and its components.

Contextual Notes

Participants are grappling with the definitions of forces involved, particularly in relation to the angle of application and the tension in the string. There is uncertainty regarding the correct approach to calculating the forces acting on the blocks.

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Homework Statement


Two blocks connected by a string are pulled
across a rough horizontal surface by a force
applied to one of the blocks.
The acceleration of gravity is 9.8 m/s2 .
1st block = 2 kg
2nd block = 8 kg
Force on second block at 52◦
μ = 0.29

[ 2kg ]-------[ 8kg ]/ 52 degrees

If each block has an acceleration of 1.6 m/s2
to the right, what is the magnitude of the
applied force? Answer in units of N.

Homework Equations


The Attempt at a Solution



What I got was 72.15 N but I got it wrong and I have no idea what I did wrong
 
Last edited:
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Draw a fbd and sum the forces for each block in the x and y.
 
Jebus_Chris said:
Draw a fbd and sum the forces for each block in the x and y.

what do i use for the force against friction for the block being pulled?
 
You need to find an expression for the normal force. In the y direction the force of gravity acts downward, the normal force acts upward, and the applied force acts upward.
 
ok for the 8kg block i got 39.30N the problem that i am having for the 2kg block is that i do not no what Force I am solving for that is pulling the block is it Fcos60 like the previous one or is it the tension of the string
 
The tension in the string is pulling the second block.
 
would you find that simply by multiplying mass times acceleration of the 2kg block?
 
Last edited:

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