How do you find the magnitude of acceleration?

[mikelison womack]

Homework Statement

. If F = 4.0 N and m = 2.0 kg, what is the magnitude a of the acceleration for the block shown below? The surface is frictionless.

Homework Equations

F=MA +/- Mg

The Attempt at a Solution

19.6[/B]

 

[Drakkith]

3. The Attempt at a Solution
19.6

Please show your work so we can identify where you've gone wrong.

 

[mikelison womack]

I really just multiplied the mass and the acceleration due to gravity and that was it .

 

[haruspex]

I really just multiplied the mass and the acceleration due to gravity and that was it .

Umm.. that shows you have not understood the question.
Your calculation finds the downward force that gravity exerts on the block. You are asked to find a horizontal acceleration, not a force, and not downward.
Can you draw a free body diagram, showing all the forces on the block?

 

[mikelison womack]

Umm.. that shows you have not understood the question.
Your calculation finds the downward force that gravity exerts on the block. You are asked to find a horizontal acceleration, not a force, and not downward.
Can you draw a free body diagram, showing all the forces on the block?

i can draw the free body diagram but i still fail to understand what's going on.

 

[haruspex]

i can draw the free body diagram but i still fail to understand what's going on.

Please either post the diagram or describe it in detail.

 

[mikelison womack]

Please either post the diagram or describe it in detail.

Is there a specific formula to calculate the acceleration in this case.

 

[Mark44]

Homework Statement

. If F = 4.0 N and m = 2.0 kg, what is the magnitude a of the acceleration for the block shown below? The surface is frictionless.View attachment 235121

Are there two 4.0N forces acting on the block, as the drawing suggests? If so, those are the forces you need to account for, not the force due to gravity (the block is on a frictionless surface).

Homework Equations

F=MA +/- Mg

The Attempt at a Solution

19.6[/B]

 

[mikelison womack]

Are there two 4.0N forces acting on the block, as the drawing suggests?

no

 

[haruspex]

Is there a specific formula to calculate the acceleration in this case.

No. Please post or describe the FBD as requested.

 

[haruspex]

no

So which one should not be there?

 

[mikelison womack]

the one showing the angle

So which one should not be there?

 

[Mark44]

Are there two 4.0N forces acting on the block, as the drawing suggests?

no

Then why does the drawing show two forces? As @haruspex said, which one shouldn't be there?

 

[mikelison womack]

Then why does the drawing show two forces? As @haruspex said, which one shouldn't be there?[/QUOTE
I don't know

 

[Drakkith]

Are there two 4.0N forces acting on the block, as the drawing suggests?

no

If that diagram is directly from your problem, then it appears that there is indeed 2 forces, each of 4 N, being applied to the block.

Is there a specific formula to calculate the acceleration in this case.

The formula doesn't change from problem to problem. It's just the normal acceleration formula $A=\frac{F_{net}}{M}$. But you have to find the total net force, not just the individual forces.

 

[mikelison womack]

If that diagram is directly from your problem, then it appears that there is indeed 2 forces, each of 4 N, being applied to the block.
The formula doesn't change from problem to problem. It's just the normal acceleration formula $A=\frac{F_{net}}{M}$. But you have to find the total net force, not just the individual forces.

so when you say find the total net force i need to add all the forces acting on the object?

 

[Drakkith]

so when you say find the total net force i need to add all the forces acting on the object?

Of course. But remember that forces only directly sum together if they are pointing in the same direction. Which they are not in this problem. How do you add two forces together that aren't pointing in the same direction?

 

[mikelison womack]

Of course. But remember that forces only directly sum together if they are pointing in the same direction. Which they are not in this problem. How do you add two forces together that aren't pointing in the same direction?

I have no clue.

 

[Drakkith]

I have no clue.

Break the forces down into their X- and Y- components. Do you know how to do that?

 

[mikelison womack]

Break the forces down into their X- and Y- components. Do you know how to do that?

Nope, I don't have the best physics teacher

 

[Drakkith]

Nope, I don't have the best physics teacher

Unfortunately it's not particularly easy to explain over a forum. Give this video a look and see if it helps:



Feel free to ask if you have any questions about this process.

 

[mikelison womack]

Unfortunately it's not particularly easy to explain over a forum. Give this video a look and see if it helps:



Feel free to ask if you have any questions about this process.

Okay, thank you.

 

[mikelison womack]

Okay, thank you.

is there an equation for magnitude.

 

[Drakkith]

is there an equation for magnitude.

Magnitude of what?

 

[Mark44]

Break the forces down into their X- and Y- components. Do you know how to do that?

Nope, I don't have the best physics teacher

Do you have a textbook? Any halfway decent book would have some worked examples like the problem you posted.