What is the Net Force on a Block Against a Wall With Static Friction?

AI Thread Summary
To determine the net force on a block against a wall with static friction, the horizontal force F must balance the forces acting on the block. The weight of the block is 5.0 N, and the coefficient of static friction is 0.25, which allows for the calculation of the maximum static friction force. The net force is the sum of the normal force and the static friction force, with the static friction acting upward to counteract the weight. A free body diagram is essential to visualize the forces, showing how the upward static friction and downward weight balance with the left/right forces from the applied force and normal force. Understanding the relationship between these forces is crucial for solving the problem effectively.
kathmill
Messages
4
Reaction score
0

Homework Statement


A horizontal force F pushes a block of weight 5.0 N aganist a vertical wall. The coefficient of static friction between the wall and the block is 0.25. The force F is the minimum required to hold the block in place.
Find the magnitude of the net force on the block by the wall (include both normal force and friction force).


Homework Equations



F = ma
Fs = coefficient of static friction * normal force.

The Attempt at a Solution



F = Fs + Fn

I don't understand how to calculate the horizontal aspect of it? Any help?

Thanks!
 
Physics news on Phys.org
Draw a free body diagram for the mass, the upward/downward forces and the left/right forces...
what keeps the mass from sliding up and down and what keeps the mass from going through the wall...
 
So the static friction force is an upward force and mg is a downward force; whereas the force applied (which I am trying to find) and the normal force are left/ right forces. But how do the up/down and left/right compare to each other?
 
Yeah you got the direction of the forces...
So what you have in essence is
http://geocities.com/hackers_007_008/Untitled.jpg
 
I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
Thread 'A cylinder connected to a hanging mass'
Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
Back
Top