Blocks, Friction Forces and Acceleration

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Homework Help Overview

The discussion revolves around a physics problem involving a block resting on a horizontal table, where a horizontal force is applied. The problem explores the concepts of friction, net force, and acceleration, specifically focusing on static and kinetic friction coefficients.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning, Problem interpretation

Approaches and Questions Raised

  • The original poster attempts to calculate the force of static friction and questions whether the block will move under the applied force. Participants discuss the transition from static to kinetic friction and the implications for net force and acceleration.

Discussion Status

Participants are actively engaging with the problem, providing guidance on the application of Newton's second law and clarifying the roles of different forces. There is a focus on understanding the net force calculation and the effects of friction.

Contextual Notes

There are indications of confusion regarding the forces acting on the block, particularly in distinguishing between static and kinetic friction. The original poster has provided specific values for forces and coefficients, but the discussion reveals a need for further clarification on these concepts.

sunnyorange
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I am having trouble with this problem:
A block whose weight is 50.0N rests on a horizontal table. A horizontal force of 25.0 N is applied to the block. The coefficients of static and kidnetic friction are 0.510 and 0.350 respectively. Will the Block move under the influence of the force and if so, what will be the block's acceleration?
What I have so far:
1. Fs=mu sN
=0.510*50
=25.5 N
25.5 N>25.0 N, therefore the block will move under the influence of the force.
2. Finding acceleration
I know I have to find the net force then use that in the second law equation. How do I do that.
I have kinetic force=17.5, mass=50/9.8=5.10 kg.
Please help!:cry:
 
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sunnyorange said:
25.5 N>25.0 N, therefore the block will move under the influence of the force

You might want to look at this again. Which one was the force due to static friction?
 
You are correct so far.

Think Newton's second law: the pulling force stays the same, but now instead of static friction, there is kinetic friction. What's the net force?
 
Would the net force be: applied horizontal force-kinetic friction force?
 
yes, that's correct (there are two other forces in the vertical direction, but Normal force and weight will balance each other in *this* situation).
 

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