Exam 6: Work and Kinetic Energy

A traveler pulls on a suitcase strap at an angle 36° above the horizontal.If of work are done by the strap while moving the suitcase a horizontal distance of 15 m,what is the tension in the strap?

The work performed as a function of time for a process is given by where What is the instantaneous power output at

In the figure,two identical springs have unstretched lengths of 0.25 m and spring constants of 300 N/m.The springs are attached to a small cube and stretched to a length L of 0.36 m as in Figure A.An external force P pulls the cube a distance to the right and holds it there.(See Figure B.)The work done by the external force P in pulling the cube is closest to

An airplane flies 120 km at a constant altitude in a direction 30.0° north of east.A wind is blowing that results in a net horizontal force on the plane due to the air of 2.40 kN in a direction 10.0° south of west.How much work is done on the plane by the air?

The force on a 3.00-kg object as a function of position is shown in the figure.If an object is moving at 2.50 m/s when it is located at ,what will its speed be when it reaches ? (Assume that the numbers on the graph are accurate to 3 significant figures.)

A 7.0-kg rock is subject to a variable force given by the equation F(x)= 6.0 N - (2.0 N/m)x + (6.0 N/m²)x² If the rock initially is at rest at the origin,find its speed when it has moved 9.0 m.

A person pushes horizontally on a heavy box and slides it across the level floor at constant velocity.The person pushes with a 60.0 N force for the first at which time he begins to tire.The force he exerts then starts to decrease linearly from 60.0 N to 0.00 N across the remaining How much total work did the person do on the box?

A 5.00-kg box slides 4.00 m across the floor before coming to rest.What is the coefficient of kinetic friction between the floor and the box if the box had an initial speed of 3.00 m/s?

A 4.0-kg object is moving with speed 2.0 m/s.A 1.0-kg object is moving with speed Both objects encounter the same constant braking force,and are brought to rest.Which object travels the greater distance before stopping?

Block A (0.40 kg)and block B (0.30 kg)are on a frictionless table (see figure).Spring 1 connects block A to a frictionless peg at 0 and spring 2 connects block A and block B.When the blocks are in uniform circular motion about 0,the springs have lengths of and ,as shown.The springs are ideal and massless,and the linear speed of block B is .If the spring constant of spring 1 is equal to ,the unstretched length of spring 1 is closest to

An unusual spring has a restoring force of magnitude ,where x is the stretch of the spring from its equilibrium length.A 3.00-kg object is attached to this spring and released from rest after stretching the spring 1.50 m.If the object slides over a frictionless horizontal surface,how fast is it moving when the spring returns to its equilibrium length?

Which of the graphs in the figure represents a spring that gets less stiff the more it is stretched?

You carry a 7.0 kg bag of groceries above the level floor at a constant velocity of 75 cm/s across a room that is room.How much work do you do on the bag in the process?

In the figure,a 900-kg crate is on a rough surface inclined at 30°.A constant external force is applied horizontally to the crate.While this force pushes the crate a distance of 3.0 m up the incline,its velocity changes from 1.2 m/s to 2.3 m/s.How much work does friction do during this process?

A graph of the force on an object as a function of its position is shown in the figure.Determine the amount of work done by this force on an object that moves from to .(Assume an accuracy of 2 significant figures for the numbers on the graph.)

Two men,Joel and Jerry,push against a wall.Jerry stops after 10 min,while Joel is able to push for 5.0 min longer.Compare the work they do.

In the figure,a 700-kg crate is on a rough surface inclined at 30°.A constant external force is applied horizontally to the crate.As the force pushes the crate a distance of up the incline,the speed changes from 1.40 m/s to 2.50 m/s.How much work does gravity do on the crate during this process?

Find the net work done by friction on the body of a snake slithering in a complete circle of radius.The coefficient of friction between the ground and the snake is 0.25,and the snake's weight is

A graph of the force on an object as a function of its position is shown in the figure.Determine the amount of work done by this force on the object during a displacement from to .(Assume an accuracy of 3 significant figures for the numbers on the graph.)

The coefficient of the restitution of an object is defined as the ratio of its outgoing to incoming speed when the object collides with a rigid surface.For an object with a coefficient of 0.78,what fraction of the object's kinetic energy is lost during a single collision?