Exam 5: Applying Newtons Laws

Kieran takes off down a 50 m high,10° slope on his jet-powered skis.The skis have a thrust of 280 N.The combined mass of skis and Kieran is 50kg (the fuel mass is negligible).Kieran's speed at the bottom is 40 m/s.What is the coefficient of kinetic friction of his skis on snow?

If I weigh 741 N on Earth and 5320 N on the surface of a nearby planet,what is the acceleration due to gravity on that planet?

A box of mass m is pulled with a constant acceleration a along a horizontal frictionless floor by a wire that makes an angle of 15 degrees above the horizontal.The tension in this wire is greater than ma.

A rope pulls on the lower block in the figure with a tension force of 20 N.The coefficient of kinetic friction between the lower block and the surface is 0.16.The coefficient of kinetic friction between the lower block and the upper block is also 0.16.What is the acceleration of the 2.0 kg block?

Jason takes off across level water on his jet-powered skis.The combined mass of Jason and skis is 75 kg (the mass of the fuel is negligible).The skis have a thrust of 200 N and a coefficient of kinetic friction on water of 0.1.Unfortunately,the skis run out of fuel after only 67 s.How far has Jason traveled when he finally coasts to a stop?

A wooden block A of mass 4.0 kg slides on a frictionless table when pulled via a massless string and pulley array by a hanging box B of mass 5.0 kg,as shown in the figure.What is the acceleration of block A as it slides on the frictionless table? Hint: Think carefully about the acceleration constraint.

You lean against a 200 kg cabinet.The coefficient of static friction between the cabinet and floor is 0.95.Will the cabinet move? Support your answer.

Three blocks, connecting ropes, and a light frictionless pulley comprise a system, as shown. An external force P is applied downward on block A. The system accelerates at the rate of 2.5 m/s². The tension in the rope connecting block B and block C equals 60 N. -In the figure above,the external force P is closest to:

A 15 kg block is on a ramp that is inclined at 20° above the horizontal.It is connected by a string to a 19 kg mass that hangs over the top edge of the ramp.Assuming that frictional forces may be neglected,what is the magnitude of the acceleration of the 19 kg block? (See the figure. )

Joe and Bill are playing tug-of-war.Joe is pulling with a force of 200 N.Bill is simply hanging on,but skidding toward Joe at a constant velocity.What is the force of friction between Bill's feet and the ground?

The figure shows a 2000 kg cable car descending a high hill.A counterweight of mass 1800 kg on the other side of the hill aids the brakes in controlling the cable car's speed.The rolling friction of both the cable car and the counterweight are negligible.How much braking force does the cable car need to descend at constant speed?

A brick initially has its largest-area face in contact with a rough surface,as shown on the left in the figure.A force F is required to pull the brick along the surface at constant speed. The brick is now flipped so that a face of smaller area is in contact,as on the right in the figure.The material of the brick is uniform on all faces.What force is now required to pull the brick along at constant speed as before?

The figure shows two 1.0 kg blocks connected by a rope.A second rope hangs beneath the lower block.Both ropes have a mass of 250 g.The entire assembly is accelerated upward at 5.5 m/s² by force .What is the tension at the bottom end of rope 1?

A car is being towed at constant velocity on a horizontal road using a horizontal chain.The tension in the chain must be equal to the weight of the car in order to maintain constant velocity.

At breakfast one morning,you notice something printed on your cereal box which says "1.0 lb = 0.454 kg." What is wrong with this information?

A block is at rest on a rough incline as shown. The frictional force acting on the block,along the incline,is

A 22 kg box must be slid across the floor.If the coefficient of static friction between the box and floor is 0.37,what is the minimum force needed to start the box moving from rest?

A 100 g ball of clay is thrown horizontally with a speed of 50.0 m/s toward a 900 g block resting on a frictionless surface.It hits the block and sticks.The clay exerts a constant force on the block during the 10.0 ms it takes the clay to come to rest relative to the block.After 10.0 ms,the block and the clay are sliding along the surface as a single system.What is the force of the clay on the block during the collision?

Consider the following figure.Assume the strings and pulleys have negligible masses and the coefficient of kinetic friction between the 2.0 kg block and the table is 0.25.What is the acceleration of the 2.0 kg block?

A rope is tied to a large crate,which is sitting on a flat surface.The coefficient of static friction between the crate and the ground is 0.9.If a person is to pull on the rope with the minimum force needed such that the crate begins to slide,the angle between the rope and the ground should be