A 72-kg skateboarder grinds down a hubba ledge that is 2.0 m long and inclined at 22 ° below the horizontal. Kinetic friction dissipates half of her initial potential energy to thermal and sound energies. Part A What is the coefficient of kinetic friction between her skateboard and the ledge surface? Express your answer to three significant figures.

A 72-kg skateboarder grinds down a hubba ledge that is 2.0 m long and inclined at 22 ° below the horizontal. Kinetic friction dissipates half of her initial potential energy to thermal and sound energies. Part A What is the coefficient of kinetic friction between her skateboard and the ledge surface? Express your answer to three significant figures.

Name: 21 1 A 72-kg skateboarder grinds down a hubba ledge that is 2.0 m long
Uploaded: 2024-03-20T06:57:25.000Z
Channel: Bartleby
Description: 21 1 A 72-kg skateboarder grinds down a hubba ledge that is 2.0 m long and inclined at 22 ° below the horizontal. Kinetic friction dissipates half of her initial potential energyto thermal and sound energies.Part AWhat is the coefficient of kinetic f

College Physics

1st Edition

ISBN:9781938168000

Author:Paul Peter Urone, Roger Hinrichs

Publisher:Paul Peter Urone, Roger Hinrichs

Chapter7: Work, Energy, And Energy Resources

Section: Chapter Questions

Problem 21PE: In a downhill ski race, surprisingly, little advantage is gained by getting a running start. (This...

See similar textbooks

Similar questions

A 7.80-g bullet moving at 575 m/s penetrates a tree trunk to a depth of 5.50 cm. (a) Use work and energy considerations to find the average frictional force that stops the bullet. (b) Assuming the frictional force is constant, determine how much time elapses between the moment the ballet enters the tree and the moment it stops moving.
Shown below is a box of mass m1 that sits on a frictionless incline at an angle above the horizontal =30. This box is connected by a relatively massless string, over a frictionless pulley, and finally connected to a box at rest over the ledge, labeled m2 . If m 1 and m2 are a height h above the ground and m2m1: (a) What is the initial gravitational potential energy of the system? (b) What is the final kinetic energy of the system?
If you run down some stairs and stop, what happens to your kinetic energy and your initial gravitational potential energy?
“ E=K+Uconstant is a special case of the work energy theorem.” Discuss this statement.
The force exerted by a diving board is conservative, provided the internal friction is negligible. Assuming friction is negligible, describe changes in the potential energy of a diving board as a swimmer dives from it, starting just before the swimmer steps on the board until just after his feet leave it.
Ignoring details associated with friction, extra forces exerted by arm and leg muscles, and other factors, we can consider a pole vault as the conversion of an athlete’s running kinetic energy to gravitational potential energy. If an athlete is to lift his body 4.8 m during a vault, what speed must he have when he plants his pole?
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.
Consider the following scenario. A car for which friction is not negligible accelerates from rest down a hill, running out of gasoline after a short distance. The driver lets the car coast farther down the hill, then up and over a small crest. He then coasts down that hill into a gas station, where he brakes to a stop and fills the tank with gasoline. Identify the forms of energy the car has, and how they are changed and transferred in this series of events. (See Figure 7.34.) Figure 7.34 A car experiencing non-negligible friction coasts down a hill, over a small crest then dill again, and comes to a stop at a gas station.
(a) Calculate the energy in kJ used by a 55.0-kg woman who does 50 deep knee bends in which her center of mass is lowered and raised 0.400 m. (She does work in both directions.) You may assume her efficiency is 20%. (b) What is the average power consumption rate in watts if she does this in 3.00 min?
At hokey puck of mass 0.17 kg is shot across a rough floor with the roughness different at different places, which can be described by a position-dependent coefficient of kinetic friction. For a puck moving along the x-axis, the coefficient of kinetic friction is the following function of x, where x is in m: (x)=0.1+0.05x . Find the work done by the kinetic frictional forte on the hockey puck when it h moved (a) from x=0 to x=2 m, and (b) from x=2 m to x=4 m.
In a downhill ski race, surprisingly, little advantage is gained by getting a running start. (This is because the initial kinetic energy is small compared with the gain in gravitational potential energy on even small hills.) To demonstrate this, find the final speed and the time taken for a skier who skies 70.0 m along a 30° slope neglecting friction: (a) Starting from rest. (b) Starting with an initial speed of 2.50 m/s. (c) Does the answer surprise you? Discuss why it is still advantageous to get a running start in very competitive events.
A block of mass m = 200 g is released from rest at point along the horizontal diameter on the inside of hemispherical bowl of radius R = 30.0 cm, and the surface of the bowl is rough (Fig. P8.23). The blocks speed at point is 1.50 m/s. Figure P8.23 (a) What is its kinetic energy at point ? (b) How much mechanical energy is transformed into internal energy as the block moves from point to point ? (c) Is it possible to determine the coefficient of friction from these results in any simple manner? (d) Explain your answer to part (c).