Concept explainers
Review. While learning to drive, you arc in a 1 200-kg car moving at 20.0 m/s across a large, vacant, level parking lot. Suddenly you realize you are heading straight toward the brick sidewall of a large supermarket and are in danger of running into it. The pavement can exert a maximum horizontal force of 7 000 N on the car. (a) Explain why you should expect the force to have a well-defined maximum value. (b) Suppose you apply the brakes and do not turn the steering wheel. Find the minimum distance you must be from the wall to avoid a collision. (c) If you do not brake but instead maintain constant speed and turn the steering wheel, what is the minimum distance you must be from the wall to avoid a collision? (d) Of the two methods in parts (b) and (c), which is better for avoiding a collision? Or should you use both the brakes and the steering wheel, or neither? Explain. (c) Does the conclusion in part (d) depend on the numerical values given in this problem, or is it true in general? Explain.
Want to see the full answer?
Check out a sample textbook solutionChapter 6 Solutions
Bundle: Physics for Scientists and Engineers with Modern Physics, Loose-leaf Version, 9th + WebAssign Printed Access Card, Multi-Term
Additional Science Textbook Solutions
College Physics
College Physics: A Strategic Approach (3rd Edition)
Conceptual Physical Science Explorations
Physics: Principles with Applications
University Physics Volume 1
Fundamentals of Physics Extended
- The engines of a tanker broke down and the wind pushes the ship with a constant speed of 1.5 m / s straight towards a reef. When the boat is 500 m from the reef, the wind stops and the engineer manages to start the engines. The rudder is stuck, so the only option is to try to accelerate backwards. The mass of the ship and its cargo is 3.6 x 107 kg and the engines produce a net horizontal force of 8 x 104 N. The hull can withstand impacts at a speed of 0.2 m / s or less. The retarding force that the water exerts on the hull of the ship can be neglected. a) The equation of motion that corresponds to the horizontal component is? b)The acceleration of the ship is equal to? c) If the reef does not exist, the vessel, before stopping, travels what distance?arrow_forwardIn the very Dutch sport of Fierljeppen, athletes run up to a long pole and then use it to vault across a canal. At the very top of his arc, a 55 kg vaulter is moving at 2.5 m/s and is 5.1 m from the bottom end of the pole. What vertical force does the pole exert on the vaulter?arrow_forwardYour forehead can withstand a force of about 6.0 kN before fracturing, while your cheekbone can withstand only about 1.3 kN. Suppose a 140 g baseball traveling at 27 m/s strikes your head and stops in 1.1 ms What force does the baseball exert on your head? What is the magnitude of the force that stops the baseball?arrow_forward
- Problem 1: A stationary 1.67-kg object is struck by a stick. The object experiences a horizontal force given by F = at - bt², where t is the time from the instant the stick first contacts the object. If a = 1.5 x 106 N/(s) and b = 2.0 x 10' N/(s)², what is the speed of the object just after it comes away from the stick at t = 0.00274 s?arrow_forwardSuppose you are at a bowling alley, where a machine uses a constant force and pushes balls up a ramp one meter in length. The balls are sliding -- not rolling -- along the incline, and they end up half a meter above the base of the ramp. Ignore friction. Approximately how much force does the machine put on a 5 kg bowling ball? 1.0 m H 0.5 m 200 N 50 N 25 N O 5N Impossible to determinearrow_forwardA girl, having a mass of 15 kg, sits motionless relative to the surface of a horizontal platform at a distance of 5 m from the platform's center. If the girl speed is 2 m/s. What is the normal force that affects the girl?arrow_forward
- A 0.087 kg arrow is fired horizontally. The bowstring exerts an average force of 80 N on the arrow over a distance of 0.90 m. With what speed does the arrow leave the bow? m/sarrow_forwardA stationary 2.17-kg object is struck by a stick. The object experiences a horizontal force given by F = at - bt 2, where t is the time in seconds from the instant the stick first contacts the object. If a = 1,500,000 N/s and b = 20,000,000 N/s?, what is the speed of the object just after it comes away from the stick at t = 2.55 x 103 s? %3Darrow_forwardA packing crate with mass 80.0 kg is at rest on a horizontal, frictionless surface. At t = 0 a net horizontal force in the +x-direction is applied to the crate. The force has a constant value of 80.0 N for 12.0 s and then decreases linearly with time so it becomes zero after an additional 6.00 s. What is the final speed of the crate, 18.0 s after the force was first applied?arrow_forward
- A 50 cm diameter 400g beach ball is dropped with a 4mg ant riding the top. The ball experiences air resistance, but the ant does not; What is the magnitude of the normal force exerted on the ant when the ball's speed is 2m/s? (C= 0.5, p = 1.2 kg/m^3)arrow_forwardA 9.50 kg block is at rest on a horizontal floor, and then you pull it with a cord that exerts a tension force of 12.0 N on the block at an angle of 24.0o above the horizontal. The coefficient of kinetic friction between the block and the floor is 0.055. What is the speed of the block 0.85 s after it starts moving? Nothing I do is working! I only have three more tries to get it right and what should be working is not.arrow_forwardAs a science fair project, you want to launch an 700 g model rocket straight up and hit a horizontally moving target as it passes 26.0 m above the launch point. The rocket engine provides a constant thrust of 17.6 N. The target is approaching at a speed of 17.0 m/s. # 3 E D 80 F3 C 4 R F 888 V % 5 F5 T G ^ 6 B ▼ Part A At what horizontal distance between the target and the rocket should you launch? Express your answer with the appropriate units. FO Provide Feedback Y Value Submit MacBook Air H HA & 7 N F7 Request Answer U ** → 8 Units DII FB 1 M wwww. ? ( 9 K DD O :) O F10 P F11 1arrow_forward
- Physics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage LearningGlencoe Physics: Principles and Problems, Student...PhysicsISBN:9780078807213Author:Paul W. ZitzewitzPublisher:Glencoe/McGraw-Hill