Finding velocity at t = 5.0s with initial velocity 2.8 m/s

[KTiaam]

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.

 

[rude man]

I got a slightly different number for distance traveled.

acceleration: how about F/m? And remember signs ...

 

[KTiaam]

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.

 

[rude man]

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.)