Which of the following statements are FALSE? A Work is a scalar physical quantity. B. Work can be negative, zero, or positive. C. When force is parallel to the displacement, the work done can be negative. D. When force is perpendicular to the displacement, the work done is zero. E. When force is parallel to the displacement, the work done can be positive. F. When force is perpendicular to the displacement, the work done can be negative. G. When force is parallel to the displacement, the work done is zero. H. When force is perpendicular to the displacement, the work done can be positive. L. The only case where the work is at maximum is when the angle between the force and displacement is zero. J. The only case where the work is at maximum is when the angle between the force and displacement is 1. K. The only case where the work is at minimum is when the angle between the force and displacement is zero. L The only case where the work is at minimum is when the angle between the force and displacement is 180 degrees. 180 degrees. choices: O AB.C.D.E.IL OC.D.E.H. I.J. K.L O F.G.H.LJ.K.L OC.D.E.F.G. HJ. K O AB.C.D.E O F.G.H.J. K

Which of the following statements are FALSE? A Work is a scalar physical quantity. B. Work can be negative, zero, or positive. C. When force is parallel to the displacement, the work done can be negative. D. When force is perpendicular to the displacement, the work done is zero. E. When force is parallel to the displacement, the work done can be positive. F. When force is perpendicular to the displacement, the work done can be negative. G. When force is parallel to the displacement, the work done is zero. H. When force is perpendicular to the displacement, the work done can be positive. L. The only case where the work is at maximum is when the angle between the force and displacement is zero. J. The only case where the work is at maximum is when the angle between the force and displacement is 1. K. The only case where the work is at minimum is when the angle between the force and displacement is zero. L The only case where the work is at minimum is when the angle between the force and displacement is 180 degrees. 180 degrees. choices: O AB.C.D.E.IL OC.D.E.H. I.J. K.L O F.G.H.LJ.K.L OC.D.E.F.G. HJ. K O AB.C.D.E O F.G.H.J. K

College Physics

11th Edition

ISBN:9781305952300

Author:Raymond A. Serway, Chris Vuille

Publisher:Raymond A. Serway, Chris Vuille

Chapter5: Energy

Section: Chapter Questions

Problem 4P: a shopper in a supermarket pushes a cart with a force of 35 N directed at an angle of 25 below the...

See similar textbooks

Similar questions

In 1990, Walter Arfeuille of Belgium lifted a 281.5-kg object through a distance of 17.1 cm using only his teeth. (a) How much work was done on the object by Arfeuille in this lift, assuming the object was lifted at constant speed? (b) What total force was exerted on Arfeuilles teeth during the lift?
Integrated Concepts (a) What force must be supplied by an elevator cable to produce an acceleration of 0.800 m/s2 against a 200-N frictional force, if the mass of the loaded elevator is 1500 kg? (b) How much work is done by the cable in lifting the elevator 20.0 m? (c) What is the final speed of the elevator if it starts from rest? (d) How much work went into thermal energy?
a shopper in a supermarket pushes a cart with a force of 35 N directed at an angle of 25 below the horizontal. The force is just sufficient to overcome various frictional forces, so the cart moves at constant speed, (a) Find the work done by the shopper as she moves down a 50.0-m length aisle, (b) What is the net work done on the cart? Why? (c) The shopper goes down the next aisle, pushing horizontally and maintaining the same speed as before. If the work done by frictional forces doesnt change, would the shoppers applied force be larger, smaller, or the same? What about the work done on the cart by the shopper?
A force F(x)=(5.0x2+7.0x)N acts on a particle as it moves along the positive x-axis. (a)How much work does the force do on the particle as it moves from x2.0 to x=5.0 m? (b) Picking a convenient reference point of the potential energy to be zero at x=, find the potential energy for this force.
In Chapter 7, the work-kinetic energy theorem, W = K, was introduced. This equation states that work done on a system appears as a change in kinetic energy. It is a special-case equation, valid if there are no changes in any other type of energy such as potential or internal. Give two or three examples in which work is done on a system but the change in energy of the system is not a change in kinetic energy.
(a) Suppose a constant force acts on an object. The force does not vary with time or with the position or the velocity of the object. Start with the general definition for work done by a force W=ifFdr and show that the force is conservative, (b) As a special case, suppose the force F =(3i + 4j)N acts on a particle that moves from O to in Figure P7.43. Calculate the work done by F on the particle as it moves along each one of the three paths shown in the figure and show that the work done along the three paths identical.
Integrated Concepts (a) Calculate the force the woman in Figure 7.46 exerts to do a push-up at constant speed, taking all data to be known to three digits. (b) How much work does she do if her center of mass rises 0.240 m? (c) What is her useful power output if she does 25 push-ups in 1 min? (Should work done lowering her body be included? See the discussion of useful work in Work, Energy, and Power in Humans. Figure 7.46 Forces involved in doing push-ups. The woman's weight acts as a force exerted downward on her center of gravity (CG).
Explorers in the jungle find an ancient monument in the shape of a large isosceles triangle as shown in Figure P9.25. The monument is made from tens of thousands of small stone blocks of density 3 800 kg/m3. The monument is 15.7 m high and 64.8 m wide at its base and is everywhere 3.60 m thick from front to back. Before the monument was built many years ago, all the stone blocks lay on the ground. How much work did laborers do on the blocks to put them in position while building the entire monument? Note: The gravitational potential energy of an objectEarth system is given by Ug = MgyCM, where M is the total mass of the object and yCM is the elevation of its center of mass above the chosen reference level.
(a) Calculate the work done on a 1500-kg elevator car by its cable to lift it 40.0 m at constant speed, assuming friction averages 100 N. (b) What is the work done on the lift by the gravitational force in this process? (c) What is the total work done on the lift?
A shopper pushes a grocery cart 20.0 m at constant speed on level ground, against a 35.0 N frictional force. He pushes in a direction 25.0° below the horizontal. (a) What is the work done on the cart by friction? (b) What is the work done on the cart by the gravitational force? (c) What is the work done on the cart by the shopper? (d) Find the force the shopper exerts, using energy considerations. (e) What is the total work done on the cart?
. In the annual Empire State Building race, contestants run up 1,575 steps to a height of 1,050 ft. In 2003, Australian Paul Crake completed the race in a record time of 9 min and 33 S, Mr., Crake weighed 143 lb (65 kg) , (a) How much work did Mr., Crake do in reaching the top of the building? (b) What was his average power output (in ft-lb/s and in hp)?
Review. You can think of the workkinetic energy theorem as a second theory of motion, parallel to Newtons 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 15.0-g bullet is accelerated from rest to a speed of 780 m/s in a rifle barrel of length 72.0 cm. (a) Find the kinetic energy of the bullet as it leaves the barrel. (b) Use the workkinetic energy theorem to find the net work that is done on the bullet. (c) Use your result to part (b) to find the magnitude of the average net force that acted on the bullet while it was in the barrel. (d) Now model the bullet as a particle under constant acceleration. Find the constant acceleration of a bullet that starts from rest and gains a speed of 780 m/s over a distance of 72.0 cm. (e) Modeling the bullet as a particle under a net force, find the net force that acted on it during its acceleration. (f) What conclusion can you draw from comparing your results of parts (c) and (e)?