Chapter 5, 6, 8, 13 + Spiral Review
Ch. 5
lifter lifts a 350-N set of weights from ground level to a position over his head, a vertical distance of 2.00 m. How much work
1.doesA weight
the weight lifter do, assuming he moves the weights at constant speed?
4. A shopper in a supermarket pushes a cart with a force of 35 N directed at an angle of 25° downward from the horizontal. Find the
work done by the shopper as she moves down a 50-m length of aisle.
from rest, a 5.00-kg block slides 2.50 m down a rough 30.0° incline. The coefficient of kinetic friction between the block and
5.theStarting
incline is μ = 0.436. Determine
(a) the work done by the force of gravity,
k
(b) the work done by the friction force between block and incline, and
Work done by an opposing force is negative (c) the work done by the normal force.
Work is only done by a parallel component of force. Normal force is perpendicular to the
displacement of the block.
7. A sledge loaded with bricks has a total mass of 18.0 kg and is pulled at constant speed by a rope. The rope is inclined at 20.0° above
the horizontal, and the sledge moves a distance of 20.0 m on a horizontal surface. The coefficient of kinetic friction between the sledge
and surface is 0.500.
(a) What is the tension of the rope?
(b) How much work is done by the rope on the sledge?
(c) What is the mechanical energy lost due to friction?
Otherwise known as the work due to friction.
8. A block of mass 2.50 kg is pushed 2.20 m along a frictionless horizontal table by a constant 16.0 N force directed 25.0° below the
horizontal. Determine the work done by
(a) the applied force,
(b) the normal force exerted by the table,
Work is only done by a parallel component of force. Normal force is perpendicular to the
displacement of the .
(c) the force of gravity, and
Work is only done by a parallel component of force. The force due to gravity is perpendicular to the
displacement of the block.
(d) the net force on the block.