Posted by kelly on Sunday, February 20, 2011 at 6:51pm.
A person on top of a wall of height 3.4 m stands near the edge, leans over and tosses a putty wad of mass 1.3 kg vertically into the air as shown in the figure below. The wad reaches a maximum of 4 m above the top of the wall. The wad then comes down and hits the ground near the bottom of the wall.
Calculate the kinetic energy of the putty wad when 1) it reaches its highest point, 2) the instant when passes the top of the wall, and 3) instant just before it hits the ground?

Physics  drwls, Sunday, February 20, 2011 at 7:03pm
1) At the highest point, V = 0
What does that tell you about the kinetic energy then?
2) When it passes the top of the wall (going dwn), it has K.E. = M g H, where H = 4 m is the maximum height thrown.
3) K.E. = M g (H + h)
where h is the height of the wall.