Calculating Force to Accelerate 6.3 kg Object at 44 m/s in 35s

[Ronaldo21]

A 6.3 kg object is accelerated from rest to speed at 44 m/s in 35s.
What average force was exerted on the object during the period of acceleration?
Answer in units of N.

i did f=mg
so f=61.75
then i divided by 35 and i got 1.764 N.
is that correct?
whats the velocity for then?

Thank you!

 

[rl.bhat]

Hi Ronaldo21, welcome to PF.
F = mg is for freely falling body. You cannot use that formula here.
Select the kinematic equation which contain initial velocity, final velocity, time and acceleration. And find the acceleration.

 

[Pengwuino]

Think about what equation you used. What does gravity, g, have to do with this? Then how would you divide a force by a time to return a force?

To get to the answer, think about what is the definition of a force and an acceleration?

 

[Ronaldo21]

OHH so i use a=(vf-vi)/change in time then??

 

[Pengwuino]

Yes, that gives you an acceleration. Then you know that F = ma, so you are one small step from finding the average force.

 

[Ronaldo21]

oh okay i get it now.
so i basicaly do 44/35 and get 1.25714
then use f=ma so 6.3 times 1.25714 and get 7.92 right?

 

[Pengwuino]

Yup, you got it.

 

[Ronaldo21]

Thank you! :d