A 54.2-kg skateboarder starts out with a speed of 1.89 m/s. He does 81.8 J of work on himself by pushing with his feet against the ground. In addition, friction does -279 J of work on him. In both cases, the forces doing the work are non-conservative. The final speed of the skateboarder is 8.69 m/s. (a) Calculate the change (PEf - PE0) in the gravitational potential energy. (b) How much has the vertical height of the skater changed? Give the absolute value. (a) Number | Units (b) Number |Units

A 54.2-kg skateboarder starts out with a speed of 1.89 m/s. He does 81.8 J of work on himself by pushing with his feet against the ground. In addition, friction does -279 J of work on him. In both cases, the forces doing the work are non-conservative. The final speed of the skateboarder is 8.69 m/s. (a) Calculate the change (PEf - PE0) in the gravitational potential energy. (b) How much has the vertical height of the skater changed? Give the absolute value. (a) Number | Units (b) Number |Units

Name: A 54.2-kg skateboarder starts out with a speed of 1.89 m/s. He does 8
Uploaded: 2024-03-20T06:57:25.000Z
Channel: Bartleby
Description: A 54.2-kg skateboarder starts out with a speed of 1.89 m/s. He does 81.8 J of work on himself by pushing with his feet against theground. In addition, friction does -279 J of work on him. In both cases, the forces doing the work are non-conservative

Principles of Physics: A Calculus-Based Text

5th Edition

ISBN:9781133104261

Author:Raymond A. Serway, John W. Jewett

Publisher:Raymond A. Serway, John W. Jewett

Chapter6: Energy Of A System

Section: Chapter Questions

Problem 1CQ

See similar textbooks

Similar questions

Describe a situation in 4iich a force is exerted for a long time but does no work. Explain.
A mouse of mass 200 g falls 100 m down a vertical mine shaft and lands at the bottom with a speed of 8.0 m/s. During its fall, how much work is done on the mouse by air resistance?
Suppose you are jogging at constant velocity. Are you doing any work on the environment and vice versa?
A particle of mass 2.0 kg moves under the influence of the force F(x)=(5x2=7x)N . Suppose a frictional force also acts on the particle. If the particle’s speed when it starts at x=4.0 m is 0.0 m/s and when it arrives at x=4.0 m is 9.0 m/s, how much work is done on it by the frictional force between x=4.0 m and x=4.0 m?
As a young man, Tarzan climbed up a vine to reach his tree house. As he got older, he decided to build and use a staircase instead. Since the work of the gravitational force mg is path Independent, what did the King of the Apes gain in using stairs?
Two forces act to double the speed of a particle, initially moving with kinetic energy of 1 J. One of the forces does 4 J of work. How much work does the other force do?
Check Your Understanding The spring Example 7.5 is compressed 6 cm from its equilibrium length. (a) Does the spring force do positive or negative work and (b) what is the magnitude?
Repeat the preceding problem, but this time, suppose that the work done by air resistance cannot be ignored. Let the work done by the air resistance when the skier goes from A to B along the given hilly path be —2000 J. The work done by air resistance is negative since the air resistance acts in the opposite direction to the displacement. Supposing the mass of the skier is 50 kg, what is the speed of the skier at point B ?
A 500-kg dragster accelerates from rest to a final speed of 110 m/s in 400 m (about a quarter of a mile) and encounters an average frictional force of 1200 N. What is its average power output in watts and horsepower if this takes 7.30s?
The surface of the preceding problem is modified so that the coefficient of kinetic friction is decreased. The same horizontal force is applied to the crate, and after being pushed 8.0 m, its speed is 5.0 m/s. How much work is now done by the force of friction? Assume that the crate starts at rest.
What is the dominant factor that affects the speed of an object that started from rest down a frictionless incline if the only work done on the object is from gravitational forces?
When jogging at 13 km/h on a level surface, a 70-kg man uses energy at a rate of approximately 850 W. Using the facts that the “human engine” is approximately 25 efficient, determine the rate at which this man uses energy when jogging up a 5.0 slope at this same speed. Assume that the frictional retarding force is the same in both cases.