Lesson 3.2 Homework
1.
A 2.0kg box is raised to a height of 3.0 m by applying a vertical force
of 50 N. Find
(a)
the work done by the applied force.
(b)
the work done by gravity
(c)
the gain in kinetic energy of the box.
(d)
the gain in potential energy of the box.
2.
A box of mass 2.0 kg initially moving at 5.0 ms
1
is acted upon by a
constant force of 25 N in the direction of motion. After some time the
speed of the box is 22 ms
1
. Calculate the work done by the force on
the box.
3.
A spring gun has a spring with a force constant of 500 Nm
1
. If this
gun is used to shoot a 25g ball straight up by compressing the spring
by 6 cm, find:
(a)
The initial kinetic energy of the ball.
(b)
The potential and kinetic energies at the highest point.
(c)
The height reached by the ball.
4.
A 2kg mass and a 5kg mass are
connected by a string that goes over a
frictionless pulley. If the two masses
are at the same height initially, find the
speed of the system when the 5kg
block has fallen through 2.0 m.
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 Fall '10
 George
 Physics, Energy, Force, Gravity, Kinetic Energy, Potential Energy, Work, 6 cm, 25 m, 3.0 m, 8.0 W, 25g

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