Finding the possible values of a force pushing a block

In summary, the block will slip down if the applied force is too small, and will slip up if the applied force is too big.
  • #1
AryRezvani
67
0

Homework Statement



35apxyx.jpg


Homework Equations



I believe the only necessary equations would be those utilized to find the X and Y components of a certain force as well as the formula used to find μs

µ = ffriction/fnormal

The Attempt at a Solution



Attempt:

I'm not really sure where to start. If someone could just give me a push in the right direction, it'd be much appreciated. :redface:
 
Physics news on Phys.org
  • #2
AryRezvani said:

Homework Statement



35apxyx.jpg


Homework Equations



I believe the only necessary equations would be those utilized to find the X and Y components of a certain force as well as the formula used to find μs

µ = ffriction/fnormal

The Attempt at a Solution



Attempt:

I'm not really sure where to start. If someone could just give me a push in the right direction, it'd be much appreciated. :redface:

In all cases, the Normal Reaction Force [to be used in the Friction = μN] is the horizontal component of the applied Force, which they called P.

Also in all cases, the vertical forces acting on the block are: mg, down, Pvert, up plus friction.

If you push with too small a force, the block will slip down, so friction will act up. When the force becomes big enough to stop the slip, Pvert, up + friction, up will equal mg, down.

If you push too hard, the block will slip up, so friction will act down. At the point of slipping

Pvert, up will equal mg, down plus friction, down

Note: Pvert, up means the vertical component of the applied force P
 
  • #3
The applied force P presses into the surface as well as along the surface.
Since the block has no acceleration into (or away from) the surface, there must be another force pointing away from the surface to oppose this.

Some people call this the "normal" force, and some the "reaction" force, at the surface.
PeterO has a slightly different picture - where the applied force is divided into normal and parallel components - which works just as well for this situation.

I'm not really sure where to start. If someone could just give me a push in the right direction, it'd be much appreciated.
The starting point is to draw a free body diagram.
It will have force arrows for weight (W), the applied force (P), and the normal/reaction (N) force and static friction (f).
[I like to give friction a lower-case "f", and I don't like subscripts.]
 

What are the units of force?

The SI unit of force is Newton (N), named after Sir Isaac Newton. Other units of force include pound-force (lbf) and dyne (dyn).

How can I calculate the force needed to push a block?

The force needed to push a block can be calculated using the formula F = ma, where F is force, m is mass, and a is acceleration. The mass of the block can be determined by weighing it, and the acceleration can be calculated by measuring the change in velocity over time.

What factors affect the amount of force needed to push a block?

The amount of force needed to push a block can be affected by factors such as the weight and mass of the block, the surface it is being pushed on, and the friction between the block and the surface. Other factors such as the angle of the push and the strength of the person pushing can also impact the force required.

How can I find the maximum and minimum possible values of force to push a block?

The maximum possible force needed to push a block would occur if the block is on a surface with high friction and the person pushing is weak. The minimum possible force would occur if the block is on a frictionless surface and the person pushing is very strong. In reality, the force required will fall somewhere between these two extremes.

What methods can I use to measure the force needed to push a block?

The force needed to push a block can be measured using a force sensor, a spring scale, or by calculating the force using the mass and acceleration as mentioned before. Alternatively, the force can also be estimated by observing how much effort is required to push the block and comparing it to known values of force in everyday life.

Similar threads

  • Introductory Physics Homework Help
Replies
11
Views
1K
  • Introductory Physics Homework Help
Replies
9
Views
12K
  • Introductory Physics Homework Help
Replies
2
Views
3K
  • Introductory Physics Homework Help
Replies
7
Views
2K
  • Introductory Physics Homework Help
Replies
7
Views
2K
  • Introductory Physics Homework Help
Replies
6
Views
908
  • Introductory Physics Homework Help
Replies
23
Views
2K
  • Introductory Physics Homework Help
Replies
5
Views
2K
  • Introductory Physics Homework Help
Replies
3
Views
1K
  • Introductory Physics Homework Help
Replies
16
Views
2K
Back
Top