Find Velocity: Help on Part B | 19.6 J, 5.0 kg, 2.8 m/s

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To find the velocity at t = 5.0 seconds for a 5.0 kg mass initially moving at 2.8 m/s, the user needed to determine acceleration. They calculated acceleration using the formula F/m, where force was derived from work divided by distance, resulting in an acceleration of -0.83 m/s². Using the equation V = V₀ + at, they found the final velocity to be -1.36 m/s. The discussion highlighted the importance of correctly applying the formulas and understanding the signs in physics calculations. The user successfully arrived at the correct answer with assistance from others in the forum.
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Homework Statement



Given the Information in the attachment and
m = 5.0 kg

a) find how far the mass moves before stoping
b) find it's velocity at t = 5.0s

i only need help on part B

Information i found from part A
distance = 4.72 meters
work = 19.6 Joules

Homework Equations


The Attempt at a Solution



I know you need to use Vo which is 2.8 m/s but I don't know what formula to use.

I was about to use:

v = vo + at

but i have no acceleration.

please help.
 

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I got a slightly different number for distance traveled.

acceleration: how about F/m? And remember signs ...
 
ah i completely forgot about

F = ma

I found Force by dividing Work over Distance

Then I used f=ma

Found a = -0.83

Then I used V = Vo + at

and got V = -1.36.

which is the answer thank you for your help

Thank you.
 
KTiaam said:
ah i completely forgot about

F = ma

I found Force by dividing Work over Distance

Then I used f=ma

Found a = -0.83

Then I used V = Vo + at

and got V = -1.36.

which is the answer thank you for your help

Thank you.

Yer' welcome. You could also have used F = 4.8cos30.

(P.S. I misread F = 4.8. You got the right answer for distance as you know by now.)
 
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