College Physics
1st Edition
ISBN: 9781938168000
Author: Paul Peter Urone, Roger Hinrichs
Publisher: OpenStax College
expand_more
expand_more
format_list_bulleted
Videos
Textbook Question
Chapter 7, Problem 21PE
In a downhill ski race, surprisingly, little advantage is gained by getting a running start. (This is because the initial kinetic energy is small compared with the gain in gravitational potential energy on even small hills.) To demonstrate this, find the final speed and the time taken for a skier who skies 70.0 m along a 30° slope neglecting friction: (a) Starting from rest. (b) Starting with an initial speed of 2.50 m/s. (c) Does the answer surprise you? Discuss why it is still advantageous to get a running start in very competitive events.
Expert Solution & Answer
Trending nowThis is a popular solution!
Students have asked these similar questions
You are working with a team that is designing a new roller coaster-type amusement park ride for a major theme park. You are present for the testing of the ride, in which an empty 150 kg car is sent along the entire ride. Near the end of the ride, the car is at near rest at the top of a 100 m
tall track. It then enters a final section, rolling down an undulating hill to ground level. The total length of track for this final section from the top to the ground is 250 m. For the first 230 m, a constant friction force of 370 N acts from computer-controlled brakes. For the last 20 m, which is
horizontal at ground level, the computer increases the friction force to a value required for the speed to be reduced to zero just as the car arrives at the point on the track at which the passengers exit.
(a) Determine the required constant friction force (in N) for the last 20 m for the empty test car.
N
(b) Find the highest speed (in m/s) reached by the car during the final section of track length…
A player kicks a football at the start of the game. After a 4 second flight, the ball touches the ground 50 m from the kicking tee. Assume air resistance is negligible and the take-off and landing height are the same (i.e., time to peak = time to fall = ½ total flight time). (Note: For each question draw a diagram to show the vector/s. Show all the step and provide units in the answers. Provide answer to 2 decimal places unless stated otherwise.) Calculate and answer all parts. Only use equations PROVIDED:
Please answer.
Chapter 7 Solutions
College Physics
Ch. 7 - Give an example of something think of as work in...Ch. 7 - Give an example of a situation in which there is a...Ch. 7 - Describe a situation in which a force is exerted...Ch. 7 - The person in Figure 7.33 does work on the lawn...Ch. 7 - Work done on a system puts energy into it Work...Ch. 7 - When solving for speed in Example 7.4, we kept...Ch. 7 - In Example 7.7, we calculated the final speed of a...Ch. 7 - Does the work you do on a book when you lift it...Ch. 7 - What is a conservative force?Ch. 7 - The force exerted by a diving board is...
Ch. 7 - Define mechanical energy. What is the relationship...Ch. 7 - What is the relationship of potential energy to...Ch. 7 - Consider the following scenario. A car for which...Ch. 7 - Describe the energy transfers and transformations...Ch. 7 - Do devices with efficiencies of less than one...Ch. 7 - List four different forms or types of energy. Give...Ch. 7 - List the energy conversions that occur when riding...Ch. 7 - Most electrical appliances are rated in watts....Ch. 7 - Explain, in terms of the definition of power, why...Ch. 7 - A spark of static electricity, such as that you...Ch. 7 - Explain why it is easier to climb a mountain on a...Ch. 7 - Do you do work on the outside world when you rub...Ch. 7 - Shivering is an involuntary response to lowered...Ch. 7 - Discuss the relative effectiveness of dieting and...Ch. 7 - What is the difference between energy conservation...Ch. 7 - If the efficiency of a coal-fired electrical...Ch. 7 - How much work does a supermarket checkout...Ch. 7 - A 75.0-kg person climbs stairs, gaining 2.50...Ch. 7 - (a) Calculate the work done on a 1500-kg elevator...Ch. 7 - Suppose a car travels 108 km at a speed of 30.0...Ch. 7 - Calculate the work done by an 85.0-kg man who...Ch. 7 - How much work is done by the boy pulling his...Ch. 7 - A shopper pushes a grocery cart 20.0 m at constant...Ch. 7 - Suppose the ski patrol lowers a rescue sled and...Ch. 7 - Compare the kinetic energy of a 20,000-kg truck...Ch. 7 - (a) How fast must a 3000-kg elephant move to have...Ch. 7 - Confirm the value given for the kinetic energy of...Ch. 7 - (a) Calculate the force needed to bring a 950-kg...Ch. 7 - A car's bumper is designed to withstand a 4.0-km/h...Ch. 7 - Boxing gloves are padded to lessen the force of a...Ch. 7 - Using energy considerations, calculate the average...Ch. 7 - A hydroelectric power facility (see Figure 7.38)...Ch. 7 - (a) How much gravitational potential energy...Ch. 7 - Suppose a 350-g kookaburra (a large kingfisher...Ch. 7 - In Example 7.7, we found that the speed of a...Ch. 7 - A 100-g toy car is propelled by a compressed...Ch. 7 - In a downhill ski race, surprisingly, little...Ch. 7 - A 5.00105 -kg subway train is brought to a stop...Ch. 7 - A pogo stick has a spring with a force constant of...Ch. 7 - A 60.0-kg skier with an initial speed of 12.0 m/s...Ch. 7 - (a) How high a hill can a car coast up (engine...Ch. 7 - Using values from Table 7.1, how many DNA...Ch. 7 - Using energy considerations and assuming...Ch. 7 - If the energy in fusion bombs were used to supply...Ch. 7 - (a) Use of hydrogen fusion to supply energy is a...Ch. 7 - The Crab Nebula (see Figure 7.41) pulsar is the...Ch. 7 - Suppose a star 1000 times brighter than our Sun...Ch. 7 - A person in good physical condition can put out...Ch. 7 - What is the cost of operating a 3.00-W electric...Ch. 7 - A large household air conditioner may consume 15.0...Ch. 7 - (a) What is the average power consumption in watts...Ch. 7 - (a) What is the average useful power output of a...Ch. 7 - A 500-kg dragster accelerates from rest to a final...Ch. 7 - (a) How long will it take an 850-kg car with a...Ch. 7 - (a) Find the useful power output of an elevator...Ch. 7 - (a) What is the available energy content, in...Ch. 7 - (a) How long would it takea 1.50105 -kg airplane...Ch. 7 - Calculate the power output needed for a 950-kg car...Ch. 7 - (a) Calculate the power per square meter reaching...Ch. 7 - (a) How long can you rapidly climb stairs...Ch. 7 - (a) What is the power output in watts and...Ch. 7 - Calculate the power output in watts and horsepower...Ch. 7 - (a) What is the efficiency of an out-of-condition...Ch. 7 - Energy that is not utilized for work or heat...Ch. 7 - Using data from Table 7.5, calculate the daily...Ch. 7 - What is the efficiency of a subject on a treadmill...Ch. 7 - Shoveling snow can be extremely taxing because the...Ch. 7 - Very large forces are produced in joints when a...Ch. 7 - Jogging on hard surfaces with insufficiently...Ch. 7 - (a) Calculate the energy in kJ used by a 55.0-kg...Ch. 7 - Kanellos Kanellopoulos flew 119 km from Crete to...Ch. 7 - The swimmer shown in Figure 7.44 exerts an average...Ch. 7 - Mountain climbers carry bottled oxygen when at...Ch. 7 - The awe-inspiring Great Pyramid of Cheops was...Ch. 7 - (a) How long can you play tennis on the 800 kJ...Ch. 7 - Integrated Concepts (a) Calculate the force the...Ch. 7 - Integrated Concepts A 75.0-kg cross-country skier...Ch. 7 - Integrated Concepts The 70.0-kg swimmer in Figure...Ch. 7 - Integrated Concepts A toy gun uses a spring with a...Ch. 7 - Integrated Concepts (a) What force must be...Ch. 7 - Unreasonable Results A car advertisement claims...Ch. 7 - Unreasonable Results Body fat is metabolized,...Ch. 7 - Construct Your Own Problem Consider a person...Ch. 7 - Construct Your Own Problem Consider humans...Ch. 7 - Integrated Concepts A 105-kg basketball player...
Additional Science Textbook Solutions
Find more solutions based on key concepts
Which of the roll owing compounds have a dipole moment of zero?
Organic Chemistry (8th Edition)
60. You are 9.0 m from the door of your bus, behind the bus, when it pulls away with an acceleration of 1.0 m/...
Physics for Scientists and Engineers: A Strategic Approach, Vol. 1 (Chs 1-21) (4th Edition)
In your own words, briefly distinguish between relative dates and numerical dates.
Applications and Investigations in Earth Science (9th Edition)
Which type of cartilage is most plentiful in the adult body?
Anatomy & Physiology (6th Edition)
2. Define equilibrium population. Outline the conditions that must be met for a population to stay in genetic e...
Biology: Life on Earth (11th Edition)
There are 25 individuals in population 1, all with genotype AA, and there are 40 individuals in population 2, a...
Campbell Biology (11th Edition)
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
- A shot putter releases a shot at 13 m/s at an angle of 42 degrees to the horizontal and from a height of 1.83 m above the ground. (Note: For each question draw a diagram to show the vector/s. Show all the step and provide units in the answers. Provide answer to 2 decimal places unless stated otherwise.) Calculate and answer all parts. Only use equations PROVIDED:arrow_forward"looks" like a particle.) ...32 GO In Fig. 22-55, positive charge q = 7.81 pC is spread uni- formly along a thin nonconducting rod of length L = 14.5 cm. What are the (a) magnitude and (b) direction (relative to the positive direction of the x axis) of the electric field produced at point P, at distance R = 6.00 cm from the rod along its perpendicular bisector? R y Р + + + + + + + + +-× L Figure 22-55 Problem 32.arrow_forward1) A horizontal wire carrying current I in +x direction on the x-axis from x=0 to x=2 2) A vertical wire carrying current I upward at along the x=2 line from y=0 to y=8 3) A diagonal straight wire started at the origin and it ends at y=8 x=2 carrying a current in SE direction ( diagonally downward); y=4x In a regional magnetic field that is given in vector notation by B = ( y i - x j )/(x^2+y^2+25) As components Bx = (y+1)/x^2+y^2+25) By = (1- x )/(x^2+y^2+25) Find the integral expression for the net force for each branch carrying 5 ampere current.arrow_forward
- An electric power station that operates at 30 KV and uses a 15:1 set step-up ideal transformer is producing 400MW (Mega-Watt) of power that is to be sent to a big city with only 2.0% loss. What which is located 270 km away is the resistance of the Two wires that are being used? 52arrow_forwardSlink, from Toy Story, is a slinky dog whose middle section is a giant spring with a spring constant of 10.9 N/m. Woody, who has a mass of 0.412 kg, grabs onto the tail end of Slink and steps off the bed (as shown in figure A) with no initial velocity and reaches the floor right as his velocity hits zero again (as shown in figure C).arrow_forwardThe character Min Min from Arms was a DLC character added to Super Smash Bros. Min Min’s arms are large springs, with a spring constant of 8.53 ⋅ 10^3 N/m, which she uses to punch and fling away her opponents. Min Min pushes her spring arm against Steve, who is not moving, compressing it 1.20 m as shown in figure A. Steve has a mass of 81.6 kg. Assuming she uses only the spring to launch Steve, how fast is Steve moving when the spring is no longer compressed? As Steve goes flying away he goes over the edge of the level, as shown in figure C. What is the magnitude of Steve’s velocity when he is 2.00 m below where he started?arrow_forward
- Calculate the energy needed to melt 50 g of 0°C icearrow_forwardTwo very long line charges are set up along lines that areparallel to the z-axis, so they set up Electric fields strictly in the xy plane. One goes throughthe x-axis at x = −0.40 m and has charge a density λ1 = +12.0 μC/m, the other goesthrough the x-axis at x = +0.40 m has charge density λ2 = −8.0 μC/m.A. Find the Electric field at point A: (0.40, 0.80) (distances in meters). Give answersin unit vector notation and draw a graph of the x-y plane with the E-fields you justfound.B. Find a point on the x-axis at which the total E-field is 0.arrow_forwardIn order to increase the amount of exercise in her daily routine, Tara decides to walk up the four flights of stairs to her car instead of taking the elevator. Each of the steps she takes are 18.0 cm high, and there are 12 steps per flight. (a) If Tara has a mass of 77.0 kg, what is the change in the gravitational potential energy of the Tara-Earth system (in J) when she reaches her car? ] (b) If the human body burns 1.5 Calories (6.28 x 10³ J) for each ten steps climbed, how much energy (in J) has Tara burned during her climb? ] (c) How does the energy she burned compare to the change in the gravitational potential energy of the system? Eburned Δυarrow_forward
- A 4.40 kg steel ball is dropped onto a copper plate from a height of 10.0 m. If the ball leaves a dent 2.75 mm deep, what is the average force exerted by the plate on the ball during the impact? Narrow_forwardA block of mass m = 7.00 kg is released from rest from point and slides on the frictionless track shown in the figure below. (Assume h₂ = 7.80 m.) a m ha 3.20 m 2.00 m i (a) Determine the block's speed at points ® and point B ©. m/s m/s point (b) Determine the net work done by the gravitational force on the block as it moves from point J A to pointarrow_forwardA 1.10 x 10²-g particle is released from rest at point A on the inside of a smooth hemispherical bowl of radius R R B 2R/3 (a) Calculate its gravitational potential energy at A relative to B. ] (b) Calculate its kinetic energy at B. ] (c) Calculate its speed at B. m/s (d) Calculate its potential energy at C relative to B. J (e) Calculate its kinetic energy at C. ] = 26.5 cm (figure below).arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
University Physics Volume 1PhysicsISBN:9781938168277Author:William Moebs, Samuel J. Ling, Jeff SannyPublisher:OpenStax - Rice University
Physics for Scientists and Engineers, Technology ...PhysicsISBN:9781305116399Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning
Principles of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning
An Introduction to Physical SciencePhysicsISBN:9781305079137Author:James Shipman, Jerry D. Wilson, Charles A. Higgins, Omar TorresPublisher:Cengage Learning
College PhysicsPhysicsISBN:9781285737027Author:Raymond A. Serway, Chris VuillePublisher:Cengage Learning
Glencoe Physics: Principles and Problems, Student...PhysicsISBN:9780078807213Author:Paul W. ZitzewitzPublisher:Glencoe/McGraw-Hill
University Physics Volume 1
Physics
ISBN:9781938168277
Author:William Moebs, Samuel J. Ling, Jeff Sanny
Publisher:OpenStax - Rice University
Physics for Scientists and Engineers, Technology ...
Physics
ISBN:9781305116399
Author:Raymond A. Serway, John W. Jewett
Publisher:Cengage Learning
Principles of Physics: A Calculus-Based Text
Physics
ISBN:9781133104261
Author:Raymond A. Serway, John W. Jewett
Publisher:Cengage Learning
An Introduction to Physical Science
Physics
ISBN:9781305079137
Author:James Shipman, Jerry D. Wilson, Charles A. Higgins, Omar Torres
Publisher:Cengage Learning
College Physics
Physics
ISBN:9781285737027
Author:Raymond A. Serway, Chris Vuille
Publisher:Cengage Learning
Glencoe Physics: Principles and Problems, Student...
Physics
ISBN:9780078807213
Author:Paul W. Zitzewitz
Publisher:Glencoe/McGraw-Hill
8.01x - Lect 11 - Work, Kinetic & Potential Energy, Gravitation, Conservative Forces; Author: Lectures by Walter Lewin. They will make you ♥ Physics.;https://www.youtube.com/watch?v=9gUdDM6LZGo;License: Standard YouTube License, CC-BY