Exam 6: Work and Kinetic Energy

A ball is thrown upward at an angle with a speed and direction such that it reaches a maximum height of above the point it was released,with no appreciable air resistance.At its maximum height it has a speed of .With what speed was the ball released?

In the figure,a constant external force P = 160 N is applied to a 20.0-kg box,which is on a rough horizontal surface.While the force pushes the box a distance of 8.00 m,the speed changes from 0.500 m/s to 2.60 m/s.The work done by friction during this process is closest to

A force on a particle depends on position such that F(x)= (3.00 N/ ) + (6.00 N/m)x for a particle constrained to move along the x-axis.What work is done by this force on a particle that moves from to ?

A spring stretches by when a object is attached.What is the weight of a fish that would stretch the spring by

A student slides her 80.0-kg desk across the level floor of her dormitory room a distance 4.00 m at constant speed.If the coefficient of kinetic friction between the desk and the floor is 0.400,how much work did she do?

Which of the graphs in the figure illustrates Hooke's Law?

You slam on the brakes of your car in a panic,and skid a certain distance on a straight,level road.If you had been traveling twice as fast,what distance would the car have skidded,under identical conditions?

A crane lifts a 425 kg steel beam vertically a distance of How much work does the crane do on the beam if the beam accelerates upward at 1.8 m/s²? Neglect frictional forces.

If a force always acts perpendicular to an object's direction of motion,that force cannot change the object's kinetic energy.

A car needs to generate in order to maintain a constant velocity of on a flat road.What is the magnitude of the total resistive force acting on the car (due to friction,air resistance,etc.)? (1 hp = 746 W)

How much energy is needed to change the speed of a 1600 kg sport utility vehicle from to ?

Consider a plot of the displacement (x)as a function of the applied force (F)for an ideal elastic spring.The slope of the curve would be

A force F = bx³ acts in the x direction,where the value of b is 3.7 N/m³.How much work is done by this force in moving an object from to

A 4.00-kg mass is attached to a very light ideal spring hanging vertically and hangs at rest in the equilibrium position.The spring constant of the spring is 1.00 N/cm.The mass is pulled downward 2.00 cm and released.What is the speed of the mass when it is 1.00 cm above the point from which it was released?

A stock person at the local grocery store has a job consisting of the following five segments: (1)picking up boxes of tomatoes from the stockroom floor (2)accelerating to a comfortable speed (3)carrying the boxes to the tomato display at constant speed (4)decelerating to a stop (5)lowering the boxes slowly to the floor. During which of the five segments of the job does the stock person do positive work on the boxes?

A constant horizontal pull acts on a sled on a horizontal frictionless ice pond.The sled starts from rest.When the pull acts over a distance x,the sled acquires a speed v and a kinetic energy K.If the same pull instead acts over twice this distance,

A 3.00-kg ball swings rapidly in a complete vertical circle of radius 2.00 m by a light string that is fixed at one end.The ball moves so fast that the string is always taut and perpendicular to the velocity of the ball.As the ball swings from its lowest point to its highest point

Calculate the minimum average power output necessary for a person to run up a long hillside,which is inclined at 25.0° above the horizontal,in 3.00 s.You can neglect the person's kinetic energy.Express your answer in horsepower.(1 hp = 746 W)

A 1500-kg car accelerates from 0 to 25 m/s in 7.0 s with negligible friction and air resistance.What is the average power delivered by the engine? (1 hp = 746 W)

A child pulls on a wagon with a horizontal force of If the wagon moves horizontally a total of in what is the average power generated by the child?