Concept explainers
Walking without slipping requires a static friction force between your feet (or footwear) and the floor. As described in this chapter, the force on your foot as you push off the floor is forward while the force exerted by your foot on the floor is backward. But what about your other foot, the one moved during a stride? What is the direction of the force on that foot as it comes into contact with the floor? Explain.
Want to see the full answer?
Check out a sample textbook solutionChapter 4 Solutions
College Physics: A Strategic Approach Technology Update, Books a la Carte Edition; Modified Mastering Physics with Pearson eText -- ValuePack Access ... Physics: A Strategic Approach (3rd Edition)
Additional Science Textbook Solutions
Essential University Physics: Volume 2 (3rd Edition)
Physics for Scientists and Engineers with Modern Physics
Conceptual Physical Science (6th Edition)
College Physics
Physics (5th Edition)
University Physics (14th Edition)
- A block of ice (m = 15.0 kg) with an attached rope is at rest on a frictionless surface. You pull the block with a horizontal force of 95.0 N for 1.54 s. a. Determine the magnitude of each force acting on the block of ice while you are pulling. b. With what speed is the ice moving after you are finished pulling? Repeat Problem 71, but this time you pull on the block at an angle of 20.0.arrow_forwardGive reasons for the answers to each of the following questions: (a) Clan a normal force be horizontal? (b) Can a normal force be directed vertically downward? (c) Consider a tennis ball in contact with a stationary floor and with nothing else. Can the normal force be different in magnitude from the gravitational force exerted on the ball? (d) Can the force exerted by the floor on the hall be different in magnitude from the force the ball exerts on the floor?arrow_forwardThree objects are connected on a table as shown in Figure P5.14. The coefficient of kinetic friction between the block of mass m2 and the table is 0.350. The objects have masses of m1 = 4.00 kg, m2 = 1.00 kg, and m3 = 2.00 kg, and the pulleys are frictionless. (a) Draw a free-body diagram of each object. (b) Determine the acceleration of each object, including its direction. (c) Determine the tensions in the two cords. What If? (d) If the tabletop were smooth, would the tensions increase, decrease, or remain the same? Explain. Figure P5.14arrow_forward
- A student takes the elevator up to the fourth floor to see her favorite physics instructor. She stands on the floor of the elevator, which is horizontal. Both the student and the elevator are solid objects, and they both accelerate upward at 5.19 m/s2. This acceleration only occurs briefly at the beginning of the ride up. Her mass is 80.0 kg. What is the normal force exerted by the floor of the elevator on the student during her brief acceleration?arrow_forwardConsider the three connected objects shown in Figure P5.43. Assume first that the inclined plane is frictionless and that the system is in equilibrium. In terms of m, g, and , find (a) the mass M and (b) the tensions T1 and T2. Now assume that the value of M is double the value found in part (a). Find (c) the acceleration of each object and (d) the tensions T1 and T2. Next, assume that the coefficient of static friction between m and 2m and the inclined plane is s and that the system is in equilibrium. Find (e) the maximum value of M and (f) the minimum value of M. (g) Compare the values of T2 when M has its minimum and maximum values. Figure P5.43arrow_forwardThree objects are connected on a table as shown in Figure P4.73. The coefficient of kinetic friction between the block of mass m2 and the table is 0.350. The objects have masses of m1 = 4.00 kg, m2 = 1.00 kg, and m3 = 2.00 kg as shown, and the pulleys are frictionless. (a) Draw a diagram of the forces on each object. (b) Determine the acceleration of each object, including its direction. (c) Determine the tensions in the two cords. (d) If the tabletop were smooth, would the tensions increase, decrease, or remain the same? Explain. Figure P4.73arrow_forward
- (a) What is the minimum force of friction required to hold the system of Figure P4.74 in equilibrium? (b) What coefficient of static friction between the 100.-N block and the table ensures equilibrium? (c) If the coefficient of kinetic friction between the 100.-N block and the table is 0.250, what hanging weight should replace the 50.0-N weight to allow the system to move at a constant speed once it is set in motion? Figure P4.74arrow_forward(a) What is the minimum force of friction required to hold the system of Figure P4.74 in equilibrium? (b) What coefficient of static friction between the 100.-N block and the table ensures equilibrium? (c) If the coefficient of kinetic friction between the 100.-N block and the table is 0.250, what hanging weight should replace the 50.0-N weight to allow the system to move at a constant speed once it is set in motion? Figure P4.74arrow_forwardA nurse pushes a cart by exerting a force on the handle at a downward angle 35.0° below the horizontal. The loaded cart has a mass of 28.0 kg, and the force of friction is 60.0 N. (a) Draw a free-body diagram for the system of interest. (b) What force must the nurse exert to move at a constant velocity?arrow_forward
- Two objects are connected by a light string that passes over a frictionless pulley as shown in Figure P4.30. Assume the incline is frictionless and take m1 = 2.00 kg, m2 = 6.00 kg, and = 55.0. (a) Draw free-body diagrams of both objects. Find (b) the magnitude of the acceleration of the objects, (c) the tension in the string, and (d) the speed of each object 2.00 s after it is released from rest. Figure P4.30arrow_forwardA setup similar to the one shown in Figure P4.53 is often used in hospitals to support and apply a traction force to an injured leg. (a) Determine the force of tension in the rope supporting the leg. (b) What is the traction force exerted on the leg? Assume the traction force is horizontal. Figure P4.53arrow_forwardA certain orthodontist uses a wire brace to align a patients crooked tooth as in Figure P4.88. The tension in the wire is adjusted to have a magnitude of 18.0 N. Find the magnitude of the net force exerted by the wire on the crooked tooth. Figure P4.38arrow_forward
- Principles of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningCollege PhysicsPhysicsISBN:9781938168000Author:Paul Peter Urone, Roger HinrichsPublisher:OpenStax CollegePhysics for Scientists and Engineers, Technology ...PhysicsISBN:9781305116399Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning
- College PhysicsPhysicsISBN:9781305952300Author:Raymond A. Serway, Chris VuillePublisher:Cengage LearningPhysics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage LearningPhysics for Scientists and Engineers with Modern ...PhysicsISBN:9781337553292Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning