1.    An aircraft carrier Nimitz has a fully loaded mass of 8.35 x 10⁷ kg. It travels a distance of 208 km in 3.5 hours. What is the average kinetic energy (in joules) of the Nimitz?

2.    You're told at school that forces that are at ninety degrees to the direction of motion don't do work. But when you push something vertically that is moving on a rough plane, you increase the friction force that is in the direction of motion. So, why doesn't this force do work? You know that cos(90) = 0, but can you explain this conceptually?

3.    Show from Newton's laws that kinetic energy = 1/2mv²

4.    Distinguish between a single fixed pulley and a single movable pulley, and describe the advantages of using each.Compare each type of pulley to its corresponding class of lever.

5.    If I push a closet that weights 800 N by a distance of 2 m on a surface without friction, the work is 1600 J.

    The same work is done if I push another closet that weights 400N by a distance of 4 m on a surface without friction.

   Can I say that I would be as tired in the first situation as in the second one, since the work is identical?

6. (i)"What is Perpetual Motion Machine? How does it work without any source of energy?
   (ii)The logic that a body can produce more energy than it consumes is strange?
   (iii)The Perpetual Motion Machine or any virtual source of energy is good concept. Also, why's the Earth's core so hot? Can we tap this energy?

A body slides with negligible friction from point A down a smooth curved ramp, starting from rest. The end of the ramp is horizontal at point B. The end of the ramp is a height h₁ below A and a height h₂ above the floor, as shown in the diagram (click here to see the diagram).
On a diagram sketch in the shape of the path taken by the body after it leaves the ramp. (1 mark)
Show that the body will hit the floor at a distance d from point O given by d = 2(h₁h₂)^-1/2. (6 marks)
Show that the body will hit the floor at an angle Ø to the horizontal given by
tan Ø = (h₂/h₁)^1/2. (5 marks)