Solving a Physics Problem: Net Work Done on a Box

[APysics]

Homework Statement

a box of mass 5.0 kg is accelerated from rest across a floor at a rate of 2.0m/s^2 for 7.0s. find the net work done on the box.

Homework Equations

f = ma
w= fdcostheta

The Attempt at a Solution

f = ma
f=10

w = fdcostheta
w=10d
w=10*v*t
w=10*v*7
w=10*a*t*7
w = 10*14*7
w=980

the answer is 490...

need help... what am i doing wrong

 

[PhanthomJay]

You set the displacement equal to vt. That is incorrect. You will need to use the correct kinematic equation for objects traveling with constant acceleration, to find the displacement.

 

[APysics]

thank you!

i got it!