Exam 4: Force

A mass M slides on a horizontal surface.A mass m is attached to a string routed over a pulley as shown below.Friction is present.When m is released,M accelerates to the right.The coefficient of friction between M and the surface is µ_k.Which one of the following statements is true?

A 2.0-kg object,initially at rest at the origin of x-y coordinate system,is subjected to two forces,F_x in the positive x-direction,and F_y in the positive y-direction,whose time-varying magnitudes are shown in graphs below.Calculate the x and y components of the object's velocity at t=2 s.

A cart slides down an incline without friction and then bounces off a bumper at the bottom.Assume that the coordinate system runs along the track with positive to the right.

A sled of mass 10 kg starts out at an initial speed of 5 m/s on a horizontal surface.The coefficient of kinetic friction with the snow is 0.05.How far does it go before it comes to a stop (within 5% accuracy)?

A mass m₁ of 5.00 kg slides on a frictionless surface.This mass is connected to another mass m₂ by a massless string over a frictionless pulley.The masses are held motionless and then released.Mass m₂ accelerates downward at 4.10 m/s².What is the mass of m₂?

A 0.5-kg model helicopter initially at rest on the ground starts to move directly up under the effect of a lift force of magnitude of 7.4 N.After 12 seconds the engine stops and the helicopter starts free fall.Ignoring air resistance,what is the maximum height the helicopter reaches?

An object with mass 5.00 kg is being pushed up an inclined plane with a constant force

A cart is being pushed down an incline with friction.What force F will accelerate it with the magnitude of the acceleration a = g down the incline? The quantities and are the coefficients of static and kinetic friction.

A 76-kg person is rappelling off a rock cliff and at one point in time has a velocity of -4.7 m/s and an acceleration of -0.89 m/s².What is the tension in the rope?

An elevator is moving upward with a constant acceleration of 1.2 m/s².An object with mass 10.kg is hanging from the ceiling of the elevator on a string.What is the tension on the string in N?

Consider two blocks hung by a massless string from a frictionless pulley as shown in the figure.The mass of block m₁ is 5 kg.The bottoms of the blocks are 20 meters above the top of the table.Mass m₂ accelerates downward at 3.5 m/s².What is the mass of m₂?

A force is applied to a 100-kg go-cart to accelerate it from 10.0 m/s to 20.0 m/s over a 7.00 s time frame.If the acceleration is assumed to be constant over the time frame,what is the magnitude of the force applied?

An 800-kg car traveling in a straight line at a speed of 30 m/s applies its brakes.During braking,there is a net force of 2000 N in the horizontal direction on the car.What distance will the car move from the time it applies its brakes until it has stopped?

A 3-kg block slides at constant velocity down a 32 ^$\circ$ inclined plane.What is the coefficient of friction between the block and the plane?

A force of 100.0 N is applied to an object of mass 85.0 kg.What is the object's acceleration?

A 100-kg object rests on a level surface with a coefficient of friction (both static and kinetic)of 0.40.If a 250 N force is applied,find the magnitude of the acceleration of the object.

A block with mass m is being pushed by a constant force F that makes an angle of $\theta$ with the horizontal as shown below.The block is moving with constant velocity on a level surface.The coefficient of kinetic friction between the block and the surface is µ_k.Which one of the following equations is correct for the magnitude of F?

An object is being pushed up an inclined plane with a constant force F = 100.N.The plane makes an angle of 30.0 ^$\circ$ with respect to the horizontal.The object is moving with constant velocity.The coefficient of kinetic friction between the object and the surface is 0.300.What is the mass of the object?

A 100-kg object moves on a level surface with a coefficient of friction of 0.40.If the initial velocity is 15 m/s,how long will it take for it to come to rest?

Two forces have magnitude 10 and 15 N and point as shown in the diagram.What is the direction of a third force which would exactly balance these two forces? That is,make the sum of the three forces zero.Measure the direction counterclockwise from the 15 N force.