Exam 7: Work and Kinetic Energy

In a ballistics test,a 28-g bullet pierces a sand bag that is Thick.If the initial bullet velocity was And it emerged from the sandbag moving at What was the magnitude of the friction force (assuming it to be constant)that the bullet experienced while it traveled through the bag?

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 the same conditions?

A 10-kg dog is running with a speed of 5.0 m/s.What is the minimum work required to stop the dog in 2.40 s?

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 What is the tension in the strap?

A child does 350 J of work while pulling a box from the ground up to his tree house at a steady speed with a light rope.The tree house is Above the ground.What is the mass of the box?

Find the net work done by friction on a box that moves in a complete circle of radius On a uniform horizontal floor.The coefficient of kinetic friction between the floor and the box is 0.25,and the box weighs

How much work must be done by frictional forces in slowing a 1000-kg car from To rest?

A 1000-kg car experiences a net force of 9500 N while slowing down from 30 m/s to 15.9 m/s. How far does it travel while slowing down?

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

How large a net force is required to accelerate a 1600-kg SUV from rest to a speed of 25 m/s in a distance of 200 m?

A truck has four times the mass of a car and is moving with twice the speed of the car.If K_t and K_c refer to the kinetic energies of truck and car respectively,it is correct to say that

When you throw a pebble straight up with initial speed V,it reaches a maximum height H with no air resistance.At what speed should you throw it up vertically so it will go twice as high?

How much kinetic energy does a 0.30-kg stone have if it is thrown at

Which one has larger kinetic energy: a 500-kg object moving at 40 m/s or a 1000-kg object moving at 20 m/s?

The graphs shown show the magnitude F of the force exerted by a spring as a function of the distance x the spring has been stretched.For which one of the graphs does the spring obey Hooke's law?

A 35-N bucket of water is lifted vertically 3.0 m and then returned to its original position.How much work did gravity do on the bucket during this process?

A force produces power P by doing work W in a time T.What power will be produced by a force that does six times as much work in half as much time?

A sled having a certain initial speed on a horizontal surface comes to rest after traveling 10 m.If the coefficient of kinetic friction between the object and the surface is 0.20,what was the initial speed of the object?

A certain car traveling at 34.0 mph skids to a stop in 29 meters from the point where the brakes were applied.In approximately what distance would the car have stopped had it been going 105.4 mph?

When a car of mass Accelerates from 10.0 m/s to some final speed,4.00 × 10⁵ J of work are done.Find this final speed.