(b) In going from its initial position to the highest point on its path, the ball moves
vertically through a distance equal to
L
, but this time the displacement is upward,
opposite the direction of the force of gravity. The work done by the force of gravity is
2
(0.341 kg)(9.80 m/s )(0.452 m)
1.51 J.
Wm
g
L
=−
(c) The final position of the ball is at the same height as its initial position. The
displacement is horizontal, perpendicular to the force of gravity. The force of gravity
does no work during this displacement.
(d) The force of gravity is conservative. The change in the gravitational potential energy
of the ballEarth system is the negative of the work done by gravity:
2
(0.341 kg)(9.80 m/s )(0.452 m)
1.51 J
Um
g
L
Δ=
−
=
−
=
−
as the ball goes to the lowest point.
(e) Continuing this line of reasoning, we find
2
(0.341 kg)(9.80 m/s )(0.452 m) 1.51 J
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This note was uploaded on 05/17/2011 for the course PHY 2049 taught by Professor Any during the Spring '08 term at University of Florida.
 Spring '08
 Any
 Physics, Force, Gravity, Work

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