Concept explainers
BIO Increasing Safety in a Collision
Safety experts say trial an automobile accident is really a succession of three separate collisions. (1) the automobile collides with an obstacle and comes to rest; (2) people within the car continue to move forward until they collide with the interior of the car, or are brought to rest by a restraint system like a seatbelt or an air bag and (3) organs within the occupants bodies continue to move forward until they collide with the body wail and are brought to rest. Not much can be done about the third collision, but the effects of the first two can be mitigated by increasing the distance over which the car and its occupants are brought to rest
For example, the severity of the first collision is reduced by building collapsible “crumple zones” into the body of a car, and by placing compressible collision barriers near dangerous obstacles like bridge supports. The second collision is addressed primarily through the use of seatbelts and air bags. These devices reduce the force that acts on an occupant to survivable levels by increasing the distance over which he or she comes to rest. This is illustrated in Figure 5-47, where we see the force exerted on a 65.0-kg driver who slows from an initial speed of 18.0 m/s (lower curve) or 36.0 m/s (upper curve) to rest in a distance ranging from 5.00 cm to 1.00 m.
90. • If both the speed and stopping distance of a driver are doubled, by what factor does the force exerted on the driver change?
- A. 0.5
- B. 1
- C. 2
- D. 4
Want to see the full answer?
Check out a sample textbook solutionChapter 5 Solutions
Physics (5th Edition)
Additional Science Textbook Solutions
Essential University Physics: Volume 1 (3rd Edition)
Glencoe Physical Science 2012 Student Edition (Glencoe Science) (McGraw-Hill Education)
The Cosmic Perspective Fundamentals (2nd Edition)
Physics for Scientists and Engineers: A Strategic Approach, Vol. 1 (Chs 1-21) (4th Edition)
The Cosmic Perspective
Introduction to Electrodynamics
- Two identical pucks collide on an air hockey table. One puck was originally at rest. (a) If the incoming puck has a speed of 6.00 m/s and scatters to an angle of 30.0°,what is the velocity (magnitude and direction) of the second puck? (You may use the result that 12=90 for elastic collisions of objects that have identical masses.) (b) Confirm that the collision is elastic.arrow_forwardTwo students hold a large bed sheet vertically between them. A third student, who happens to be the star pitcher on the school baseball team, throws a raw egg at the center of the sheet. Explain why the egg does not break when it hits the sheet, regardless of its initial speed.arrow_forwardProfessional Application One hazard of space travel is debris left by previous missions. There are several thousand objects orbiting Earth that are large enough to be detected by radar, but there are far greater numbers of very small objects, such as flakes of paint. Calculate the force exerted by a 0.100-mg chip of paint that strikes a spacecraft window at a relative speed of 4.00103 m/s, given the collision lasts 6.00108 s.arrow_forward
- You have just planted a sturdy 2-m-tall palm tree in your front lawn for your mother's birthday. Your brother kicks a 500 g ball, which hits the top of the tree at a speed of 5 m/s and stays in contact with it for 10 ms. The ball falls to the ground near the base of the tree and the recoil of the tree is minimal. (a) What is the force on the tree? (b) The length of the sturdy section of the root is only 20 cm. Furthermore, the soil around the roots is loose and we can assume that an effective force is applied at the tip of the 20 cm length. What is the effective force exerted by the end of the tip of the root to keep the tree from toppling? Assume the tree will be uprooted rather than bend. (c) What could you have done to ensure that the tree does not uproot easily?arrow_forwardUnreasonable Results Squids have been reported to jump from the ocean and travel 30.0 m (measured horizontally) before re-entering the water. (a) Calculate the initial speed of the squid if it leaves the water at an angle of 20.0°, assuming negligible lift from the air and negligible air resistance. (b) The squid propels itself by squirting water. What fraction of its mass would it have to eject in order to achieve the speed found in the previous part? The water is ejected at 12.0 m/s; gravitational force and friction are neglected. (c) What is unreasonable about the results? (d) Which premise is unreasonable, or which premises are inconsistent?arrow_forward5)arrow_forward
- A light cart, moving to the right and a heavy cart, moving to the left at the same speed, collide and stick together. Which direction will the carts travel after the collision? a) To the left b) To the right c) The carts will not move. d) Impossible to determine without knowing the speed.arrow_forwardQuantitative Question T'Challah, Luke, and Knausgaard are on low-friction roller skates, engaging in a series of stunts. At one point, Luke is on Knausgaard's left and T'Challah is on his right. They all push out. Knausgaard ends up moving left at 2 m/s, Luke moves left at 5 m/s, and T'Challah moves right at 4 m/s. T'Challah's mass is 90 kg, Luke's is 75 kg, and Knausgaard's is 80 kg. a) How fast were they all drifting before they pushed each other? Assume that they were all moving together. b) What was the impulse that was exerted on T'Challah? c) What impulse did T'Challah exert on Knausgaard? d) What impulse did Luke exert on Knausgaard?arrow_forward36) A 3 kg ball moving to the right on a frictionless table at 5 m/s makes a head on collision with another 3 kg ball with a velocity of 4 m/s to the left. If the collision is perfectly inelastic. i) Draw the velocity diagram before collision reflecting the quantities involved ii) Draw the force diagram identifying the forces during collision iii) Draw the velocity diagram after collisionarrow_forward
- Equipment Access to the Internet Calculator App Introduction According to legend, Galileo Galilei dropped two balls of different mass from the top of the leaning tower of Pisa in 1589. Whether or not this public experiment ever took place, Galileo was able to demonstrate that, contrary to Aristotle’s teaching, all bodies fall at the same rate regardless of mass, assuming that one is not so tenuous that it is slowed by air resistance. In this experiment, an equation is presented relating the acceleration of gravity at Earth’s surface, g, to the height that an object falls from, h, and the time it takes the object to reach the ground, t. Gravity acceleration at Earth’s surface has been measured many times. In British Imperial Units, Small Metric Units, and Large Metric Units, the standard values of g are: g = 32 feet per second-squared (ft/s2) g = 980 centimeters per second-squared (cm/s2) g = 9.8 meters per second-squared (m/s2). Theory…arrow_forwardA large man and a small boy stand facing each other on frictionless ice. They put their hands together and push against each other so that they move apart. Who moves away with the higher speed? a) The small boy b) The large man c) Both move with equal speeds. d) Not enough informationarrow_forwardASAP PLZZarrow_forward
- Principles of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningPhysics for Scientists and Engineers with Modern ...PhysicsISBN:9781337553292Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningPhysics for Scientists and EngineersPhysicsISBN:9781337553278Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning
- University Physics Volume 1PhysicsISBN:9781938168277Author:William Moebs, Samuel J. Ling, Jeff SannyPublisher:OpenStax - Rice UniversityCollege PhysicsPhysicsISBN:9781938168000Author:Paul Peter Urone, Roger HinrichsPublisher:OpenStax CollegePhysics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage Learning