5.3 A hockey stick applies a constant force over a distance of 0.121 m to an initially stationary puck, of mass 152 g. The puck
moves with a speed of 51.0 m/s. With what force did the hockey stick strike the puck?
N5.4 At the Aircraft Landing Dynamics Facility located at NASA's Langley Research Center in Virginia, a water-jet nozzle propels a
46,000 kg sled from zero to 400 km/hour in 2.5 seconds. (This sled is equipped with tires that are being tested for the space
shuttle program, which are then slammed into the ground to see how they hold up.) (a) Assuming a constant acceleration for
the sled, what distance does it travel during the speeding-up phase? (b) What is the net work done on the sled during the time
interval?(a) m
(b) J5.5 A 25.0 kg projectile is fired by accelerating it with an electromagnetic rail gun on the Earth's surface. The rail makes a 30.0
degree angle with the horizontal, and the gun applies a 1250 N force on the projectile for a distance of 7.50 m along the rail.
(a) Ignoring air resistance and friction, what is the net work done on the projectile, by all the forces acting on it, as it moves
7.50 m along the rail? (b) Assuming it started at rest, what is its speed after it has moved the 7.50 m?
(a) J
(b) m/s5.6 The force of gravity acts on a 1250 kg probe in outer space. It accelerates the probe from a speed of 225 m/s to 227 m/s over
a distance of 6750 m. How much work does gravity do on the probe?
JSection 7 - Interactive problem: work-kinetic energy theorem
7.1 Use the information given in the interactive problem in this section to answer the following question. What force is required for
the skier to make the jump? Test your answer using the simulation.
NSection 9 - Power
9.1 How much power would be required to hoist a 48 kg couch up to a 22 m high balcony in 5.0 seconds? Assume it starts and
ends at rest.
W
9.2 Stuntman's Freefall, a ride at Six Flags Great Adventure in New Jersey, stands 39.6 meters high. Ignoring the force of
friction, what is the minimum power rating of the motor that raises the 1.20×10^5 kg ride from the ground to the top in 10.0
seconds at a constant velocity?
W9.3 Lori, who loves to ski, has rigged up a rope tow to pull herself up a local hill that is inclined at an angle of 30.0 degrees from
the horizontal. The motor works against a retarding frictional force of 100 N. If Lori has a mass of 60.5 kg, and the power of
the motor is 1350 W, at what speed can the motor pull her up the hill?m/s9.4 A power plant supplies 1,100 megawatts of power to the electric grid. How many joules of energy does it supply each
second?
J9.5 How much work does a 5.00 horsepower outboard motor do in one minute? State your answer in joules.
J9.6 The Porsche® 911 GT3 has a 380 hp engine and a mass of 1.4×10^3 kg. The car can accelerate from 0 to 100 km/h in 4.3
seconds. What percentage of the power supplied by the engine goes into making the car move? Assume that the car's
acceleration is constant and that there are 746 Watts/hp.
%
Section 10 - Potential energy
10.1 You get paid $1.25 per joule of work. How much do you charge for moving a 10.0 kg box up to a shelf that is 1.50 meters off
the ground?
$