Physics 163

Unit 5: Work, Energy and Power

Problem Set A

The following selection of problems are sample problems. Individual student problem sets will vary since numerical information is randomly-generated.

Directions:

For the following problems:

• Compute the unknown quantity and enter the answer in the blank.
• Use 9.8 m/s/s for the numerical value of g for situations upon Earth
• Do not round any computed numbers until the last calculation.
• Enter your answers accurate to the second decimal place (unless told otherwise).

Problem 1:

A rightward force of 258 N is applied to a 59.8-kg object to displace it to the right for a distance of 3.18 meters. Determine the work (in Joules) done upon the object.

Problem 2:

Renatta Gass applies a rightward force of 717 Newtons to her 1158 kg car to displace it rightward across the ice. She does a total of 49821 Joules of work on the car. Determine the displacement (in meters) of the car.

Problem 3:

A 5.17-kg object is tied to a rope and lifted vertically upward at a constant speed of 1.7 m/s for a displacement of 23.9 m. Determine the work (in Joules) done upon the object.

Problem 4:

Hans Full is pulling on a rope to drag his backpack to school across the ice. He pulls upwards and rightwards with a force of 27.9 Newtons at an angle of 45 degrees to drag his backpack a horizontal distance of 179.2 meters to the right. Determine the work (in Joules) done upon the backpack.

Problem 5:

Anna Litical is doing the It's All Uphill Lab. She applies a 17.9-Newton force parallel to the inclined plane in order to pull a cart up a hill inclined at an angle of 53 degrees. If she drags the cart a distance of 1.39 meters, then how much work (in Joules) does she do upon the cart?

Problem 6:

A 379.2 gram squirrel does 43 pushups, displacing itself by a distance of 11.9 cm for each pushup. Determine the total work (in Joules) done on the squirrel while moving upward. (Enter your answer accurate to the third decimal place. Avoid rounding until the end.)

Problem 7:

Jack runs up the stairs, elevating his 71.8 kg body a vertical distance of 2.39 meters in a time of 1.59 seconds. Determine the power (in Watts) done by the stairs on Jack's body.

Problem 8:

During peak shopping season at Northbrook Court, an escalator elevates 1396 passengers a vertical distance of 8.28 meters over the course of 27.9 minutes. If the average mass of the passengers are 53.9 kg, determine the power (in Watts) delivered by the escalator to the people.

Problem 9:

Determine the kinetic energy (in Joules) of Renatta Brainze, a 52.9 kg skydiver who is falling with a speed of 41.8 m/s from a height of 6982 feet.

Problem 10:

Big Bubba has a kinetic energy of 1955 Joules. Determine his speed (in m/s) if he has a mass of 151 kg and a potential energy of 698 Joules.

Problem 11:

A 279 gram ball reaches a peak height of 27.9 m. Determine the potential energy (in Joules) of the ball at the peak.

Problem 12:

Li Ping Phar, the esteemed Chinese ski jumper, has a mass of 47.9 kg. He is moving with a speed of 23.9 m/s at a height of 43.9 meters above the ground. Determine the total mechanical energy (in Joules) of Li Ping Phar.

Problem 13:

A 1.79 gram baseball is moving upward with a speed of 57.9 m/s when at a height of 85.8 meters above the ground. Determine the total mechanical energy (in Joules) of the baseball.

Problem 14:

A worker applies a 179 N force to lift a 37.9 kg object to a height of 3.18 meters at a constant speed of 1.4 m/s. What is the increase in potential energy of the object (in Joules)?

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