Variable formula question... Why does W2 = 24W1??? 1. "To accelerate a certain car from rest to the speed v requires the work W1. The work needed to accelerate the car from v to 5v is W2. Which of the following is correct?" 2. The only forumulas I can think of that deal with work are: W = Fd F = ma a = v/t ...So if you tried to replace the F with velocity terms, you could get: W1 = m(v/t)d ...Now they say that W2 = [m(5v/t)d] - [m(v/t)d] They say W2 is the the work needed to accelerate v *TO* 5v, so is that right...? So W2 = m(4v/t)d, yes? :/ So, if I switch the v/t back to force, then: W2 = m(4a)(d) W2 = (F/4)(d) So W1 = (F)(d) and W2 = (F/4)(d) Or, 4W2 = Fd = W1 So, it seems like 4W2 = W1 BUT THIS IS COMPLETELY NOT RIGHT! =_= I don't get this problem at all! Help me, somebody! The answer's supposed to be W2 = 24W1 !!! UGH! Thank you!!!