The longer you spend reading and thinking about this question,
the more defective it appears.
-- In each case, the amount of work done is determined by the strength
of
the force AND by the distance the skateboard rolls <em><u>while you're still
</u></em>
<em><u>applying the force</u>. </em>Without some more or different information, the total
distance the skateboard rolls may or may not tell how much work was done
to it.<em>
</em>
-- We know that the forces are equal, but we don't know anything about
how far each one rolled <em>while the force continued</em>. All we know is that
one force must have been removed.
-- If one skateboard moves a few feet and comes to a stop, then you
must have stopped pushing it at some time before it stopped, otherwise
it would have kept going.
-- How far did that one roll while you were still pushing it ?
-- Did you also stop pushing the other skateboard at some point, or
did you stick with that one?
-- Did each skateboard both roll the same distance while you continued pushing it ?
I don't think we know enough about the experimental set-up and methods
to decide which skateboard had more work done to it.
Answer:
F=m x a
(F is force ,M is mass and A is acceleration)
in thisncase the Mass is given but we need to find ou the acceleration
Formula for acceleration-
a=(v - u)/t
(v is final velocity , u is initiatal velocity and t is time)
a = (0 - 80)/4
a= -80/4
a= -20
By substituting the values-
F= m x a
F= 1500 x -20
F=-30000N
Thus the force acted is -30000N
hope this helps
