Explain in detail when work done is positive and work done is negative and under what circumstances (if any) is no work done (zero) on a moving object even though a net force acts on it? 2. One sometimes speaks of the "direction of time", evolving from past to future. Does this mean that time is a vector quantity? Explain your reasoning. 3. The acceleration of a certain moving object is constant in magnitude

Explain in detail when work done is positive and work done is negative and under what circumstances (if any) is no work done (zero) on a moving object even though a net force acts on it? 2. One sometimes speaks of the "direction of time", evolving from past to future. Does this mean that time is a vector quantity? Explain your reasoning. 3. The acceleration of a certain moving object is constant in magnitude

Glencoe Physics: Principles and Problems, Student Edition

1st Edition

ISBN:9780078807213

Author:Paul W. Zitzewitz

Publisher:Paul W. Zitzewitz

Chapter11: Energy And Its Conservation

Section: Chapter Questions

Problem 79A

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B. Answer the following questions in complete sentence. 1.Is the layman concept of work the same as its scientific counterpart? 2. When is work really done? 3. How can we strategically increase the work done on an object?
1. Can you please THOROUGHLY explain how did you solve this? I need it in step by step format because I'm going to explain it in class. Please help me, thank you Answers: (a) the speed of players as they hit the ground is 23.1877 m/s (b) total work done = 36265.8 J. (c) the value of final kinetic energy is 36265.8 J. D) Therefore the net combined power by both men exerted at middle is 2212.593 joules. E) Work done on Person101 is 22,389.8 joules and Work done on Person 212 is 13912.9 joules.
A roller-coaster car shown in the following figure is pulled up to point 1 where it is released from rest. Assuming no friction, calculate the speed at points 2, 3, and 4. please show your work, including diagrams, algebraic equations, and enough written explanations that somebody who is not familiar with the problem could understand what you are doing.
A skier of mass 80 kg is pulled up a slope by a motor-driven cable. A) How much work is required to pull him 70 m up a 30° slope (assumed frictionless) at a constant speed of 2.7 m/s? B) (b) What power (expressed in hp) must a motor have to perform this task? NOTE: I was able to answer part A, needed help with part B. Thank you !
Remember to include given information, basic equations, calculations, and solutions with correct units for full credit. You are NOT to use kinematics unless otherwise stated. Captain Marvel races through the atmosphere with a speed of 200. m/s on her way to Wakanda to help the cause. If she requires 1,450 N of force in order to travel at this constant speed, a. how much power does she expend? b. If she slows to a stop and her mass is 65.0 kg, how far did she travel when stopping if she used the same force as above?
1. How much work is needed to horizontally move a 1,200 kN box in constant speed? The frictional force is 100 N. Show your complete solution.
A 1000 kg car traveling at 40 m/s slows to 15 m/s. What is the initial kinetic energy of the car? What is the final kinetic energy of the car? How much work is done on the car in slowing it down? What force does the work on the car? Please use a diagram so i can better understand.
Sketch the following scenarios and use the appropriate formulas to solve a) what is the kinetic energy of a 3kg object moving at 4 m/s? B) a 4kg object possesses 18j of kinetic energy what is its velocity?
I just need help with D and E A guy on a bike moves up a ramp as shown above. The total mass of the guy and bike is 150 kg. A. What happens to his kinetic energy as he goes up the ramp? B. What happens to his gravitational potential energy as he goes up the ramp? C. What happens to his total energy as he goes up the ramp? D. What is the height, h, that he reaches? E. If his mass were to double, what height would he reach?
(JUST SOLVE PART (d,e,f)) You can think of the work−kinetic energy theorem as a second theory of motion, parallel to Newton's laws in describing how outside influences affect the motion of an object. In this problem, solve parts (a), (b), and (c) separately from parts (d) and (e) so you can compare the predictions of the two theories. A 15.8-g bullet is accelerated from rest to a speed of 723 m/s in a rifle barrel of length 74.6 cm. (a) Find the kinetic energy of the bullet as it bullet as it leaves the barrel=4.12956 (b) Use the work-kinetic energy theorem to find the net work that is done on the bullet=4.12956 (c) Use the result to part (b) to find the magnitude of the average net force that acted on the bullet while it was in the barrel=5.5356 (d) Now model the bullet as a particle under constant acceleration. Find the constant acceleration of the bullet that starts from rest and gains a speed of 723 m/s over a distance of 74.6 cm. (e) Modeling the bullet as a particle under a net…
Using a cable with a tension of 1270 N, a tow truck pulls a car 5.00 km along a horizontal roadway. You do not have to show your work. Part A How much work does the cable do on the car if it pulls horizontally? Part B How much work does the cable do on the car if it pulls at 35.0∘ above the horizontal? Part C How much work does the cable do on the tow truck if it pulls horizontally? Part D How much work does the cable do on the tow truck if it pulls at 35.0∘ above the horizontal? Part E How much work does gravity do on the car in part A?
Please answer all 3 subparts. 1. A robot begins pushing a 10kg box that was already moving at 0.5m/s [Right] along a surface with a coefficient of kinetic friction of 0.15. The robot pushes with only 30N [Right] of force. a) What is the acceleration of the box? b) Using the Work-Energy theorem, calculate how much work the robot does on the box accelerating it from 0.5m/s [Right] to 2m/s [Right]. c) What distance did the robot push the box? Use kinematics to check your work.