Please someone check to see if on the right track: A woman lifts a barbell 2.0m in 5.0s, beginning and ending at rest. If she lifts the same distance in 10s, the work done by her is: I said it would be four times as much because I used 1/2mv^2. I placed the v I calculated from v=d/t into the kinetic equation. (.4)^2 (.2)^2 .16 is four times as much as .04. Is this right. A 2kg block is thrown upward from a point 20m above the earth's surface. At what height above the earth's surface will the gravitational potential energy of the earth-block systme have increased by 500J. work: mgh= 2(9.81)(20m)= 392.4 --> potential 500J= mgh 500J = (2kg)(9.81) (h) h= 25m If someone could point me in the right direction of how to do this problem I would appreciate it. Thank you.