College Physics
2nd Edition
ISBN: 9780134601823
Author: ETKINA, Eugenia, Planinšič, G. (gorazd), Van Heuvelen, Alan
Publisher: Pearson,
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Textbook Question
Chapter 4, Problem 21P
A 60-kg student sitting on a hardwood floor does not slide until pulled by a 240-N horizontal force. Determine the coefficient of static friction between the student and floor.
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Check out a sample textbook solutionStudents have asked these similar questions
a) A delivery truck with two stacked crates in the back brakes quickly. The crate on the bottom just barely stays put on the floor of the truck. Does the top crate stay put or does it fall off? The top crate has a mass of 27.0 kg and the mass of the bottom crate is 22.0 kg. The coefficient of static friction between the bottom crate and the truck is 0.420, and the coefficient of kinetic friction for that surface is 0.350. The coefficient of static friction between the crates is 0.400, and the coefficient of kinetic friction is 0.320.
Hint: Don’t forget about Newton’s 3rd Law especially when dealing with friction between the two crates
b) The top crate will slide off if it moves more than 87.5 cm. If the truck braked for 1.84 s did the top crate slide off? If not, how far did it move?
A 78 kg crate rests on a rough horizontal surface. The coefficient of static friction and coefficient of kinetic friction are 0.3 and 0.2, respectively.
What would happen if the applied horizontal force is 200 N?
Choices:
It will remain at rest.
The frictional force will be neglected.
It will accelerate in the same direction as the horizontal force.
It will accelerate in the opposite direction as the horizontal force.
The 137-lb force P is applied to the 240-lb crate, which is stationary before the force is applied. Determine the magnitude and
direction of the friction force F exerted by the horizontal surface on the crate. The friction force is positive if to the right, negative if to
the left.
Assume μ = 0.51, Mk = 0.39.
P
Answer: F =
i
Mk
lb
Chapter 4 Solutions
College Physics
Ch. 4 - Review Question 4.1 When does a vector have a...Ch. 4 - Review Question 4.2 The x- and y-components of...Ch. 4 - Review Question 4.3 What is the force of friction...Ch. 4 - Review Question 4.4 For problems involving objects...Ch. 4 - Review Question 4.5 Why do we need to resolve the...Ch. 4 - Review Question 4.6
You read in this section that...Ch. 4 - 1. A car accelerates along a road. Identify the...Ch. 4 - 2. A person pushes a 10-kg crate exerting a 200-N...Ch. 4 - Compare the ease of pulling a lawn mower and...Ch. 4 - 4. You simultaneously release two balls: one you...
Ch. 4 - You shoot an arrow with a bow. The following is...Ch. 4 - In what reference frame does a projectile launched...Ch. 4 - In Table 4.6 we found that the two balls touched...Ch. 4 - 8. While running at constant velocity, how should...Ch. 4 - 9. You hold a block on a horizontal, frictionless...Ch. 4 - 10. In the process described in the previous...Ch. 4 - Suppose that two blocks are positioned on an...Ch. 4 - 12. A box containing some stones is resting on a...Ch. 4 - For the following two questions, the answer...Ch. 4 - 14. A block is resting on a rough inclined...Ch. 4 -
15. A box with a heavy television set in it...Ch. 4 - 16. How can an Atwood machine be used to determine...Ch. 4 - 17. Your friend is on Rollerblades holding a...Ch. 4 - Explain why a car starts skidding when a driver...Ch. 4 - 19. Explain why old tires need to be replaced.
Ch. 4 - 20. Explain how friction helps you to walk.
Ch. 4 - 21. Explain why you might fall forward when you...Ch. 4 - Explain why you might fall backward when you slip.Ch. 4 - Explain why the tires of your car can spin out...Ch. 4 - You throw two identical balls simultaneously at...Ch. 4 - 25. Your friend says that the vertical force...Ch. 4 - Your friend says that a projectile launched at an...Ch. 4 - An object of mass m1 placed on an inclined plane...Ch. 4 - 28 An object of mass m1 placed on an inclined...Ch. 4 - 29. A horse is pulling a sled. If the force...Ch. 4 - 30. If you kick a block so that it starts moving...Ch. 4 - Determine the x- and y-components of each force...Ch. 4 - 2. Determine the x- and y-components of each force...Ch. 4 - * Determine the x- and y-components of each...Ch. 4 - 4 * The x- and y-components of several unknown...Ch. 4 - * The x- and y-scalar components of several...Ch. 4 - 6. * Three ropes pull on a knot shown in Figure...Ch. 4 - * Figure P4.7 shows an unlabeled force diagram for...Ch. 4 - For each of the following situations, draw the...Ch. 4 - * Write Newtons second law in component form for...Ch. 4 - For the situations described here, construct a...Ch. 4 - * Write Newtons second law in component form for...Ch. 4 - Apply Newtons second law in component form for the...Ch. 4 - Apply Newtons second law in component form for the...Ch. 4 - 14. * Equation Jeopardy 1 The three sets of...Ch. 4 - * You exert a force of 100 N on a rope that pulls...Ch. 4 - 16. * You exert a force of a known magnitude F on...Ch. 4 - * Olympic 100-m dash start At the start of his...Ch. 4 - 18. * Your own accelerometer A train has an...Ch. 4 - * EST Finn and Hazel are using a battery-powered...Ch. 4 - A 91.0-kg refrigerator sits on the floor. The...Ch. 4 - A 60-kg student sitting on a hardwood floor does...Ch. 4 - Car stopping distance and friction A car traveling...Ch. 4 - 23. * A 50-kg box rests on the floor. The...Ch. 4 - 24. * Marsha is pushing down and to the right on a...Ch. 4 - * You want to determine the coefficient of kinetic...Ch. 4 - * A wagon is accelerating to the right. A book is...Ch. 4 - s. Determine an expression for the minimum...Ch. 4 - * A car has a mass of 1520 kg. While traveling at...Ch. 4 - m/s2 when pulled by a rope exerting a 120-N force...Ch. 4 - 30. ** A crate of mass m sitting on a horizontal...Ch. 4 - * EST You absentmindedly leave your book bag on...Ch. 4 - 32. * Block 1 is on a horizontal surface with a...Ch. 4 - 33. * You want to use a rope to pull a 10-kg box...Ch. 4 - 34. * A car with its wheels locked rests on a...Ch. 4 - 35. Olympic skier Olympic skier Tina Maze skis...Ch. 4 - * Another Olympic skier Bode Miller. 80-kg...Ch. 4 - * A book slides off a desk that is tilted 15...Ch. 4 - * Helge, Steve, and Heidi are sitting on a sled on...Ch. 4 - 40. * When traveling on an airplane you get meals...Ch. 4 - 41. Skier A 52-kg skier starts at rest and slides...Ch. 4 - 42. * Ski rope tow You agree to build a backyard...Ch. 4 - 43. * Soapbox racecar A soapbox derby racecar...Ch. 4 - 44. * A person is pushing two carts that are...Ch. 4 - 45. * BIO Whiplash Experience A car sitting at...Ch. 4 - Iditarod race practice The dogs of four-time...Ch. 4 - angle above the horizontal. The other end of the...Ch. 4 - * Rope 1 pulls horizontally, exerting a force of...Ch. 4 - * Three sleds of masses m1,m2,m3 are on a smooth...Ch. 4 - 50. ** Repeat Problem 4.49 , only this time with...Ch. 4 - 51. * A skier is moving down a snowy hill with an...Ch. 4 - ** A person holds a 200-g block that is connected...Ch. 4 - 53. ** Two blocks of masses are connected to each...Ch. 4 - 54. ** The 20-kg block shown in Figure P4.54 ...Ch. 4 - * A squirrel jumps of a roof in the horizontal...Ch. 4 - * A frog jumps at an angle 30 above the...Ch. 4 - 57. A bowling ball rolls off a table. Draw a force...Ch. 4 - 58 * A tennis ball is served from the back line of...Ch. 4 - 59. * Equation Jeopardy 3 The equations below...Ch. 4 - 60 * EST An airplane is delivering food to a small...Ch. 4 - A ball moves in an arc through the air (see Figure...Ch. 4 - A marble is thrown as a projectile at an angle...Ch. 4 - 63 * Marbles are exiting a container through a...Ch. 4 - * Robbie Knievel ride On May 20, 1999, Robbie...Ch. 4 - 65. * Daring Darless wishes to cross the Grand...Ch. 4 - * A football punter wants to kick the ball so that...Ch. 4 - 67. * If you shoot a cannonball from the same...Ch. 4 - 68. When you actually perform the experiment...Ch. 4 - 69. * You can shoot an arrow straight up so that...Ch. 4 - 70. * Robin Hood wishes to split an arrow already...Ch. 4 - 71. * Three force diagrams for a car on a road are...Ch. 4 - * A minivan of mass 1560 kg starts at rest and...Ch. 4 - 74. * Emily pulls a 5-kg block across a rough...Ch. 4 - 75. * EST You abruptly push a 1.7-kg book along a...Ch. 4 - 76 ** EST In the situation of Problem 4.75,...Ch. 4 - 78. * Two blocks of masses and hang at the ends...Ch. 4 - 79. * A 3.5-kg object placed on an Inclined plane...Ch. 4 - above the horizontal) is connected by a string...Ch. 4 - above the horizontal) is connected by a string...Ch. 4 - 82 ** You are driving at a reasonable constant...Ch. 4 - 84. * In the situation of Problem 2.71 (Chapter 2...Ch. 4 - 87. * Your friend has a pie on the roof of his...Ch. 4 - * A ledge on a building is 20 m above the ground....Ch. 4 - 89. * You are hired to devise a method to...Ch. 4 - The mass of a spacecraft is about 480 kg. An...Ch. 4 - incline When she reaches the level floor at the...Ch. 4 - * Tell all A sled starts at the top of the hill...Ch. 4 - Professor tests airplane takeoff speed D. A....Ch. 4 - Professor tests airplane takeoff speed D A Wardle,...Ch. 4 - Professor tests airplane takeoff speed D A Wardle,...Ch. 4 - Professor tests airplane takeoff speed D. A....Ch. 4 - Choose the best velocity-versus-time graph below...Ch. 4 - Ski jumping in Vancouver The 2010 Olympic ski...Ch. 4 - Ski jumping in Vancouver The 2010 Olympic ski...Ch. 4 - Ski jumping in Vancouver The 2010 Olympic ski...Ch. 4 - Assume that the skier left the ramp moving...Ch. 4 - Ski jumping in Vancouver The 2010 Olympic ski...
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