Finding final Velocity given mass, force, and displacement

In summary, to find the final velocity of a 2.78 kg block pulled from rest by a 15.8 N force on a horizontal surface with a coefficient of kinetic friction of .106, one can use the equation Vf=sqrt((2*W)/m) where W is the work (w=Fx*deltax) and m is the mass of the block. The final velocity can be calculated to be 5.7 m/s after traveling a distance of 2.88 m. The net force, rather than the coefficient of kinetic friction, should be used in the calculation of work.
  • #1
Bearbull24.5
50
0

Homework Statement



2.78 kg block is pulled (from rest) by a force (horizontal surface) of 15.8 N. The coefficient of kinetic friction is .106. What is the velocity after 2.88 m?

Homework Equations


fk=N(uk)
Vf=sqrt((2*W)/m



The Attempt at a Solution



I attempted to find the final velocity by first finding the work (w=Fx*deltax) and then plugging it into the Vf equation I have listed.
 
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  • #2
Hi Bearbull24.5! :smile:

(have a mu: µ and a square-root: √ and a delta: ∆ :wink:)
Bearbull24.5 said:
fk=N(uk)
Vf=sqrt((2*W)/m

I attempted to find the final velocity by first finding the work (w=Fx*deltax) and then plugging it into the Vf equation I have listed.

That should be ok (assuming that m is inside the bracket). :confused:

What figures did you get?
 
  • #3
I got 5.7 for the final velocity and a work of 45.504 N m
 
  • #4
Do I need to use the coefficient of kinetic friction for anything?
 
  • #5
Bearbull24.5 said:
I got … work of 45.504 N m

No, you need to use the net force. :wink:
 

1. How do I calculate final velocity given mass, force, and displacement?

The formula for calculating final velocity is v = sqrt(2F/m) * s, where v is final velocity, F is force, m is mass, and s is displacement.

2. Can I use this formula for any type of motion?

Yes, this formula can be used for any type of motion as long as the mass, force, and displacement are known.

3. What units should I use for mass, force, and displacement?

Mass should be in kilograms (kg), force should be in Newtons (N), and displacement should be in meters (m).

4. How do I know if my final velocity calculation is correct?

You can double-check your calculation by using the units of measurement. The final velocity should have units of meters per second (m/s).

5. Can I use this formula for objects with changing mass or force?

No, this formula is only applicable for objects with constant mass and force. If the mass or force changes during the motion, the formula will not give an accurate result.

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