Concept explainers
If your car is stuck in the mud and you don't have a winch to pull it out, you can use a piece of rope and a tree to do the trick. First, you tie one end of the rope to your car and the other to a tree, then pull as hard as you can on the middle of the rope, as shown in Figure P4.68 a. This technique applies a force to the car much larger than the force that you can apply directly. To see why the car experiences such a large force, look at the forces acting on the center point of the rope, as shown in Figure P4.68 b. The sum of the forces is zero, thus the tension is much greater than the force you apply. It is this tension force that acts on the car and, with luck, pulls it free.
Figure P4.68
70. Assume that you are pulling on the rope but the car is not moving. What is the approximate direction of the force of the mud on the car?
A. North
B. South
C. East
D. West
Want to see the full answer?
Check out a sample textbook solutionChapter 4 Solutions
COLL PHYSICS UPDATE V2&S/WRKBK&MOD MST/
Additional Science Textbook Solutions
Conceptual Physical Science (6th Edition)
The Cosmic Perspective
Essential University Physics: Volume 2 (3rd Edition)
Physics for Scientists and Engineers with Modern Physics
Physics for Scientists and Engineers: A Strategic Approach with Modern Physics (4th Edition)
Cosmic Perspective Fundamentals
- A 276-kg glider is being pulled by a 1 950-kg jet along a horizontal runway with an acceleration of a = 2.20 m/s2 to the right as in Figure P4.41. Find (a) the thrust provided by the jets engines and (b) the magnitude of the tension in the cable connecting the jet and glider. Figure P4.41arrow_forwardAn object of mass m1 = 5.00 kg placed on a frictionless, horizontal table is connected to a string that passes over a pulley and then is fastened to a hanging object of mass m2 = 9.00 kg as shown in Figure P4.28. (a) Draw free-body diagrams of both objects. Find (b) the magnitude of the acceleration of the objects and (c) the tension in the string. Figure P4.28arrow_forwardTwo blocks, each of mass m, are hung from the ceiling of an elevator as in Figure P4.33. The elevator has an upward acceleration a. The strings have negligible mass. (a) Find the tensions T1 and T2 in the upper and lower strings in terms of m, a, and g. (b) Compare the two tensions and determine which string would break first if a is made sufficiently large. (c) What are the tensions if the cable supporting the elevator breaks? Figure P4.33 Problems 33 and 34.arrow_forward
- A car accelerates down a hill (Fig. P4.57), going from rest to 30.0 m/s in 6.00 s. A toy inside the car hangs by a string from the cars ceiling. The ball in the figure represents the toy, of mass 0.100 kg. The acceleration is such that the string remains perpendicular to the ceiling. Determine (a) the angle and (b) the tension in the string. Figure P4.57arrow_forwardA particle with mass m = 4.20 kg accelerates according to a = (−3.50 + 2.20) m/s2. (a) What is the net force acting on the particle? (Express your answer in vector form.) F =?N (b) What is the magnitude of this force ?Narrow_forwardA block is pushed across a horizontal surface by the force F with constant velocity. F = 20 N, θ = 30°, and M = 10 kg. What is the magnitude of the normal force on the block? choices: 88 N 20 N 108 N 98 N 94 Narrow_forward
- A small boat is crossing a lake on a windy day. During some interval of time, the boat undergoes the given displacement Δ?⃗ .Δr→. Δ?⃗ =(3.19 m)ı̂ +(2.89 m)ȷ̂ Δr→=(3.19 m)ı^+(2.89 m)ȷ^ During the same interval of time, the wind exerts the given constant force ?⃗ F→ on the boat. ?⃗ =(261 N)ı̂ −(125 N)ȷ̂arrow_forwardReview. A block of mass m = 2.00 kg is released from rest at h = 0.500 m above the surface of a table, at the top of a = 30.0 incline as shown in Figure P4.53. The frictionless incline is fixed on a table of height H = 2.00 m. (a) Determine the acceleration of the block as it slides down the incline. (b) What is the velocity of the block as it leaves the incline? (c) How far from the table will the block hit the floor? (d) What time interval elapses between when the block is released and when it hits the floor? (e) Does the mass of the block affect any of the above calculations? Figure P4.53 Problems 53 and 59arrow_forwardIn Figure P4.35, the man and the platform together weigh 950 N. The pulley can be modeled as frictionless. Determine how hard the man has to pull on the rope to lift himself steadily upward above the ground. (Or is it impossible? If so, explain why.) Figure P4.35arrow_forward
- (a) What is the resultant force exerted by the two cables supporting the traffic light in Figure P4.75? (b) What is the weight of the light? Figure P4.75arrow_forwardIn Figure P4.53, the incline has mass M and is fastened to the stationary horizontal tabletop. The block of mass m is placed near the bottom of the incline and is released with a quick push that sets it sliding upward. The block stops near the top of the incline as shown in the figure and then slides down again, always without friction. Find the force that the tabletop exerts on the incline throughout this motion in terms of m, M, g, and .arrow_forward(a) What is the resultant force exerted by the two cables supporting the traffic light in Figure P4.75? (b) What is the weight of the light? Figure P4.75arrow_forward
- Principles of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningCollege PhysicsPhysicsISBN:9781305952300Author:Raymond A. Serway, Chris VuillePublisher:Cengage LearningPhysics for Scientists and Engineers, Technology ...PhysicsISBN:9781305116399Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning
- Physics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage LearningCollege PhysicsPhysicsISBN:9781285737027Author:Raymond A. Serway, Chris VuillePublisher:Cengage Learning