1. The problem statement, all variables and given/known data 1. A frictionless slope has a hypotenuse of 2.0m and a height of 1.0m. A box of mass 40kg is pushed up along the hypotenuse with a force of 250N. Since work done is defined as the product of the force and the distance moved by the object in the direction of the force, we can say that work done is 2.0 x 250, which gives us 500J. However, all of the work done should be converted to G.P.E. and G.P.E. is only 1.0 x g (10N/kg) x 40 = 400J. Where is the 100J? There is no friction of any kind. 2. If you rub a comb and place it near a trickling stream of water, you will notice that the water bends towards the comb. This is mainly due to polarity. But water has 2 polarities, a negative one and a positive one, so it could bend towards the comb and at the same time, move away from the comb. But why does it bend towards? 3. If you rub a balloon and stick it to the curtain, after some time, will it drop? Why will it drop? 2. The attempt at a solution 1. Where is the 100J? Work done - G.P.E.? 2. 2 polarities, so why does it bend? 3. My guess is it will not drop since there is electrostatic attraction between the balloon and the curtain and since the balloon is an insulator, electric charges are not able to move from balloon to curtain.