Exam 5: Forces and Motion II: Applications

A horizontal force is used to push an object of mass m up an inclined plane. The angle between the plane and the horizontal is $\theta$ . The normal reaction force of the plane acting on the mass m is

A box M = 20 kg) is sitting on a horizontal surface. It is connected to a massless hook by a light string passing over a massless pulley wheel. The coefficients of friction between the box and the surface are 0.80 static) and 0.30 kinetic). If 15 kg in total) are placed on the hook, calculate the acceleration of the box.

A block of wood is pulled by a horizontal string across a rough surface at a constant velocity with a force of 20 N. If the coefficient of kinetic friction between the surfaces is 0.2, what is the weight of the wooden block?

A block of mass m_b rests on a horizontal surface and is accelerated by means of a horizontal cord that passes over a frictionless peg to a hanging weight of mass m_w. The coefficient of kinetic friction between the block and the horizontal surface is µ_k and the tension in the cord is T. The acceleration of the block is given by

An object traveling in a circle at constant speed

The figure shows a top view of a ball on the end of a string traveling counterclockwise in a circular path. Assume that air resistance is negligible. The free-body diagram that best represents the net force acting on the ball is

If a jet plane doubles the speed, the drag force on the jet plane

The free-body diagram that best represents the forces acting on the student sliding down a rough incline is

A proud new Jaguar owner drives her car at a speed of 25 m/s into a corner. The coefficients of friction between the road and the tires are 0.70 static) and 0.40 kinetic). What is the minimum radius of curvature for the corner in order for the car not to skid?

A heavy truck and a light car are traveling at the same speed on the same roadway. If the coefficients of static friction between their tires and the road are the same, which vehicle will be able to stop in the shortest distance? Assume both have the same braking force.

Two objects are sliding at the same speed across a wooden surface. The coefficient of kinetic friction between the first object and the surface is twice that between the second object and the surface. The distance traveled by the first object before it stops is S. The distance traveled by the second object is

A block slides down a frictionless incline. The path at the bottom of the incline is an arc of a circle. Using the compass rose, the direction of the net force on the block at the bottom of the arc point P) is along

An object with a mass of 5.5 kg is allowed to slide from rest down an inclined plane. The plane makes an angle of 30 ^o with the horizontal. The coefficient of friction between the plane and the object is 0.35. The acceleration of the object is

Four identical blocks are moving on a surface for which the coefficient of kinetic friction between each block and the surface is µ_k. The velocity of each block is indicated by the vector on the block. For which block is the force of friction between the surface and the block greatest?

A car going around a curve of radius R at a speed V experiences a centripetal acceleration a_c. What is its acceleration if it goes around a curve of radius 3R at a speed of 2V?

A block of mass m is pulled in the direction shown in the figure across a rough surface at a constant velocity. The magnitude of the frictional force is

A ball of mass m is attached to a thin string and whirled in a vertical circle or radius r. The tension in the string at point e where the ball is moving with speed v is

A particle moving uniformly along a curved path has a period of 0.24 s and a speed of 4.2 m/s. The radius of the path of the particle is

A 2.0 kg-book is on the floor of an elevator. If the elevator is accelerating upward at a rate of , the normal force acting on the book by the floor is

A mass m is placed on a rough incline at an angle $\theta$ to the horizon. A force F is applied up the incline, to prevent the mass from sliding down the incline, and it is just enough to prevent the mass from sliding down the incline. Using the compass rose, the direction of the frictional force is along