MASTERPHYS:KNIGHT'S PHYSICS ACCESS+WKB
4th Edition
ISBN: 9780135245033
Author: Knight
Publisher: PEARSON
expand_more
expand_more
format_list_bulleted
Concept explainers
Videos
Textbook Question
Chapter 7, Problem 31EAP
Your 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 30 m/s strikes your head and Stops in 1.5 ms.
a. What is the magnitude of the force that stops the baseball?
b. What force does the baseball exert on your head? Explain.
c. Are you in danger of a fracture if the ball hits you in the forehead? On the cheek?
Expert Solution & Answer
Learn your wayIncludes step-by-step video
schedule05:22
Students have asked these similar questions
on an unknown planet, a 145 g baseball is hit so that it travels straight upward to reach a maximum height of 15.6 m after being struck by the bat. A fan observes that it takes 2.90 s for the ball to reach its maximum height.
A. what is the initial velocity of the baseball
B. What is the acceleration due to gravity on this planet
2. You pull with a force of 255 N on a rope that is attached to a
block of mass 30 kg, and the block slides across the floor at a
constant speed of 1.1 m/s. The rope makes an angle of 0 = 40°
with the horizontal. Both the force and the velocity of the block
are in the xy plane. The block moves only along the direction
parallel to the floor. See the figure for a diagram of this situation.
a. What is the net force on the block? Explain your
b.
c.
reasoning.
Is there friction between the block and the floor? How do you know?
Rope
40°
15₂
Draw a Free Body Diagram for the block. Find the magnitude and direction of each force,
and express them as vectors.
You stand on the edge of a cliff and hold two metal balls, one in each hand. The mass and size of the metal
spheres are the same and we ignore the air resistance. One ball, ball 1, you drop outside the cliff. The other ball,
ball 2, you throw straight up. Which statement is correct for the acceleration of the metal balls after they have left
your hands:
A. a, = a2
B. a, > a,
C. a, < a,
D. a, = -a,
%3D
Chapter 7 Solutions
MASTERPHYS:KNIGHT'S PHYSICS ACCESS+WKB
Ch. 7 - You find yourself in the middle of a frozen lake...Ch. 7 - How does a sprinter sprint? What is the forward...Ch. 7 - How does a rocket take off? What is the upward...Ch. 7 - How do basketball players jump straight up into...Ch. 7 - A mosquito collides head-on with a car traveling...Ch. 7 - A mosquito collides head-on with a car traveling...Ch. 7 - A small car is pushing a large truck. They are...Ch. 7 - A very smart 3-year-old child is given a wagon for...Ch. 7 - Teams red blue are having a tug-of-war. According...Ch. 7 - Will hanging a magnet in front of the iron cart in...
Ch. 7 - FIGURE Q7.11 shows two masses at rest. The string...Ch. 7 - FIGURE Q7.12 shows two masses at rest. The string...Ch. 7 - The hand in FIGURE Q7.13 is pushing on the back of...Ch. 7 - A and B in FIGURE Q7.14 are connected by a...Ch. 7 - In case a in FIGURE Q7.15, block A is accelerated...Ch. 7 - For Exercises 1 through 5: a. Draw an interaction...Ch. 7 - For Exercises 1 through 5: a. Draw an interaction...Ch. 7 - For Exercises I through 5: a. Draw an interaction...Ch. 7 - For Exercises 1 through 5: a. Draw an interaction...Ch. 7 - For Exercises 1 through 5: a. Draw an interaction...Ch. 7 - a. How much force does an 80 kg astronaut exert on...Ch. 7 - Block B in FIGURE EX7.7 rests on a surface for...Ch. 7 - A 1000 kg car pushes a 2000 kg truck that has a...Ch. 7 - with masses of 1 kg, 2 kg, and 3 kg are lined up...Ch. 7 - A 3000 kg meteorite falls toward the earth. What...Ch. 7 - The foot of a 55 kg sprinter is on the ground for...Ch. 7 - A steel cable lying flat on the floor drags a 20...Ch. 7 - An 80 kg spacewalking astronaut pushes off a 640...Ch. 7 - The sled dog in FIGURE EX7.14 drags sleds A and B...Ch. 7 - Two-thirds of the weight of a 1500 kg car rests on...Ch. 7 - FIGURE EX7.16 shows two 1.0 kg blocks connected by...Ch. 7 - What is the tension in the rope of Figure EX7.17?...Ch. 7 - A 2.0-m-long, 500 g rope pulls a 10 kg block of...Ch. 7 - A woman living in a third-story apartment is...Ch. 7 - Two blocks are attached to opposite ends of a...Ch. 7 - The cable cars in San Francisco are pulled along...Ch. 7 - A 2.0 kg rope hangs from the ceiling. What is the...Ch. 7 - A mobile at the art museum has a 2.0 kg steel cat...Ch. 7 - The 1.0 kg block in FIGURE EX7.24 is tied to the...Ch. 7 - The 100 kg block in FIGURE EX7.25 takes 6.0 s to...Ch. 7 - FIGURE P7.26 shows two strong magnets on opposite...Ch. 7 - FIGURE P7.27 shows a 6.0 N force pushing two...Ch. 7 - 28. A rope of length L and mass m is suspended...Ch. 7 - Prob. 29EAPCh. 7 - 30. A Federation starship (2.0 × 106 kg) uses its...Ch. 7 - Your forehead can withstand a force of about 6.0...Ch. 7 - Bob, who has a mass of 75 kg, can throw a 500 g...Ch. 7 - Two packages at UPS start sliding down the 20°...Ch. 7 - The two blocks in FIGURE P7.34 are sliding down...Ch. 7 - The coefficient of static friction is 0.60 between...Ch. 7 - The block of mass M in FIGURE P7.36 slides on a...Ch. 7 - The 10.2 kg block in FIGURE P7.37 is held in place...Ch. 7 - The coefficient of kinetic friction between the...Ch. 7 - FIGURE P7.39 shows a block of mass m resting on a...Ch. 7 - A4.0 kg box is on a frictionless 35° slope and is...Ch. 7 - Prob. 41EAPCh. 7 - The 2000 kg cable car shown in FIGURE P7.42...Ch. 7 - The century-old ascensores in Valparaiso, Chile,...Ch. 7 - A 3200 kg helicopter is flying horizontally. A 250...Ch. 7 - A house painter uses the chair-and-pulley...Ch. 7 - A long, 1.0 kg rope hangs from a support that...Ch. 7 - Prob. 47EAPCh. 7 - Prob. 48EAPCh. 7 - Find an expression for the magnitude of the...Ch. 7 - Prob. 50EAPCh. 7 - Prob. 51EAPCh. 7 - Prob. 52EAPCh. 7 - The lower block in FIGURE CP7.53 is pulled on by a...Ch. 7 - Prob. 54EAPCh. 7 - Prob. 55EAPCh. 7 - A 40-cm-diameter, 50-cm-tall, 15 kg hollow...Ch. 7 - 57. FIGURE CP7.57 shows a 200 g hamster sitting on...Ch. 7 - Prob. 58EAP
Additional Science Textbook Solutions
Find more solutions based on key concepts
1.3 Obtain a bottle of multivitamins and read the list of ingredients. What are four chemicals from the list?
Chemistry: An Introduction to General, Organic, and Biological Chemistry (13th Edition)
MAKE CONNECTIONS The gene that causes sickle-cell disease is present in a higher percentage of residents of su...
Campbell Biology (11th Edition)
Explain all answers clearly, with complete sentences and proper essay structure if needed. An asterisk (*) desi...
Cosmic Perspective Fundamentals
HOW DO WE KNOW? In this chapter, we focused on extranuclear inheritance and how traits can be determined by gen...
Concepts of Genetics (12th Edition)
7. Which bones form via intramembranous ossification?
a. Irregular bones
b. Certain flat bones
c. Long bones
d....
Human Anatomy & Physiology (2nd Edition)
Describe an example of bioconversion. What metabolic processes can result in fuels?
Microbiology: An Introduction
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, physics and related others by exploring similar questions and additional content below.Similar questions
- The International Space Station has a mass of approximately 370,000 kg. (a) What is the force on a 150-kg suited astronaut if she is 20 m from the center of mass of the station? (b) How accurate do you think your answer would be?arrow_forwardA cart filled with sand rolls at a speed of 1.0 m/s along a horizontal path without friction. A ball of mass m = 2.0 kg is thrown with a horizontal velocity of 8.0 m/s toward the cart as shown in Figure P11.79. The ball gets stuck in the sand. What is the velocity of the cart after the ball strikes it? The mass of the cart is 15 kg. FIGURE P11.79 Problems 79 and 80.arrow_forwardIn a head-on, inelastic collision, a 4,000-kg truck going 10 m/s east strikes a 1,000-kg car going 20 m/s west. (a) What is the speed and direction of the wreckage? (b) How much kinetic energy was lost in the Collision?arrow_forward
- A rope hangs down from a high tree branch at the edge of a river. Josh, who has mass 65 kg, trots at 2.5 m/s to the edge of the river, grabs the rope 7.2 m below where it is tied to the branch, and swings out over the river.a. What is the minimum time that Josh must hang on to make it back to shore?b. What is the maximum tension in the rope?arrow_forward1. Sam, whose mass is 75 kg, takes off across level snow on his jet-powered skis. The skis have a thrust of 200 N and a coefficient of kinetic friction on snow of 0.10. Unfortunately, the skis run out of fuel after only 10 s. A. What is Sam’s top speed? B. How far has Sam traveled when he finally coasts to a stop?arrow_forwardIII A sled starts from rest at the top of the frictionless, hemi- spherical, snow-covered hill shown in FIGURE CP10.74. a. Find an expression for the sled's speed when it is at angle . b. Use Newton's laws to find the maximum speed the sled can have at angle without leaving the surface. c. At what angle max does the sled "fly off" the hill? FIGURE CP10.74 $ Rarrow_forward
- 1. A carnival ride consists of a hollow cylinder spinning about a vertical axis. As the cylinder spins with a speed vo, a person of mass M rides the inside wall of the cylinder without slipping down (there is no floor). The distance of the center of mass of the person from the axis of the cylinder is R. a. Draw the free body diagram of forces acting on the person during the ride. Show your choice for the +x and +y directions. b. Write out Newton's 2nd law in the x and y directions. Set the RHS of the equations to zero or Mv²/R or –Mv²/R. X: y: c. What is the normal force? d. What is the magnitude and direction of the friction force that the wall exerts on the rider? e. What is the magnitude and direction of the friction force the rider exerts on the wall? f. The coefficient of static friction between the wall and the rider is µg. What is the minimum speed that the rider can move without slipping down the wall?arrow_forwardMost geologists believe that the dinosaurs became extinct 65 million years ago when a large comet or asteroid struck the earth, throwing up so much dust that the sun was blocked out for a period of many months. Suppose an asteroid with a diameter of 2.0 km and a mass of 0.50 × 10¹3 kg hits the earth (6.0 x 1024 kg) with an impact speed of 4.4 x 10 m/s. ▾ Part A What is the earth's recoil speed after such a collision? (Use a reference frame in which the earth was initially at rest.) Express your answer with the appropriate units. ► View Available Hint(s) v=3.2 10 D IT HA Submit Part B V = -8 Previous Answers X Incorrect; Try Again; 3 attempts remaining Submit m What percentage is this of the earth's speed around the sun? The earth orbits the sun at a distance of 1.5 x 10¹¹ m. Express your answer as a percentage. ► View Available Hint(s) IVE ΑΣΦ Provide Feedback S ? ? % of the earth's speed Next >arrow_forwardA block of mass m is dropped from the fourth floor of an office building and subsequently hits the ground with speed v. From which floor is the mass dropped to double the impact speed? a. The tenth floor. b. The sixth floor. c. The sixteenth floor. d. The twelfth floor. e. The eighth floor. If an object of mass m moves with constant speed v, the net force on the object is: a. mv b. ma c. mg d. None of these answers is correct e. 0arrow_forward
- Jeric, a professional rooftop futbol player, kicked a 4.0 [kg] ball off a rooftop that is 50 [m] off the ground,at 10 [m/s] oriented 30° degree above his horizon. His pal, Joshua, caught the ball from a window at adistant building that is 25 [m] off the ground. Joshua then released the ball from this height and let theball fall to the ground.A. What is the speed of the ball just before it reaches Joshua? B. What is the speed of the ball just before it reaches the ground?arrow_forwardA cube of mass m = 61 kg slides along a horizontal surface. The coefficient of friction between the cube and the surface is μk = 0.41. The cube has an initial speed of vo = 18 m/s in the positive x-direction as shown. a. Write an expression for the x-component of the frictional force the cube experiences, Ff, in terms of the given variables and variables available in the palette. b. What is the magnitude of the frictional force in N? c. How far will the cube travel, in meters, before coming to rest?arrow_forwardWrecking balls are used to demolish old buildings. A 720 kg steel ball is suspended from a 10-m-long cable on a crane. A hook on the crane slowly pulls the ball back, then releases it. The ball's speed at the lowest point in its arc, just before striking the building, is 4.5 m/s Part A At the lowest point in the ball's arc, O the tension in the cable is less than mg because the ball is moving down. O the tension in the cable is equal to mg because tension and gravity are the only forces and they balance. O the tension in the cable is greater than mg because there has to be a net upward force. Submit Part B What is the tension in the cable when the ball is at its lowest point? Express your answer with the appropriate units. ► View Available Hint(s) T = Request Answer li μÀ Submit Value Units ?arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
Physics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage Learning
Physics for Scientists and Engineers, Technology ...PhysicsISBN:9781305116399Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning
University Physics Volume 1PhysicsISBN:9781938168277Author:William Moebs, Samuel J. Ling, Jeff SannyPublisher:OpenStax - Rice University
Glencoe Physics: Principles and Problems, Student...PhysicsISBN:9780078807213Author:Paul W. ZitzewitzPublisher:Glencoe/McGraw-Hill
College PhysicsPhysicsISBN:9781285737027Author:Raymond A. Serway, Chris VuillePublisher:Cengage Learning
Physics for Scientists and Engineers: Foundations...
Physics
ISBN:9781133939146
Author:Katz, Debora M.
Publisher:Cengage Learning
Physics for Scientists and Engineers, Technology ...
Physics
ISBN:9781305116399
Author:Raymond A. Serway, John W. Jewett
Publisher:Cengage Learning
University Physics Volume 1
Physics
ISBN:9781938168277
Author:William Moebs, Samuel J. Ling, Jeff Sanny
Publisher:OpenStax - Rice University
Glencoe Physics: Principles and Problems, Student...
Physics
ISBN:9780078807213
Author:Paul W. Zitzewitz
Publisher:Glencoe/McGraw-Hill
College Physics
Physics
ISBN:9781285737027
Author:Raymond A. Serway, Chris Vuille
Publisher:Cengage Learning
Length contraction: the real explanation; Author: Fermilab;https://www.youtube.com/watch?v=-Poz_95_0RA;License: Standard YouTube License, CC-BY