Exam 7: Newtons Third Law

In a ballistics test,a 1.50-g bullet is fired through a 28.0-kg block traveling horizontally toward the bullet.In this test,the bullet takes 11.4 ms to pass through the block as it reverses the block's velocity from 1.75 m/s to the right to 1.20 m/s to the left with constant acceleration.Find the magnitude of the force that the bullet exerts on the block during this ballistics test.

On a horizontal frictionless floor,a worker of weight 0.900 kN pushes horizontally with a force of 0.200 kN on a box weighing 1.80 kN.As a result of this push,which statement could be true?

Two unequal masses M and m (M > m)are connected by a light cord passing over a pulley of negligible mass,as shown in the figure.When released,the system accelerates.Friction is negligible.Which figure below gives the correct free-body force diagrams for the two masses in the moving system?

A series of weights connected by very light cords are given an upward acceleration of 4.00 m/s² by a pull P,as shown in the figure.A,B,and C are the tensions in the connecting cords.The pull P is closest to

Three objects are connected by massless wires over a massless frictionless pulley as shown in the figure.The tension in the wire connecting the 10.0-kg and 15.0-kg objects is measured to be 133 N.What is the tension in wire A?

A series of weights connected by very light cords are given an upward acceleration of 4.00 m/s² by a pull P,as shown in the figure.A,B,and C are the tensions in the connecting cords.The SMALLEST of the three tensions,A,B,and C,is closest to

Block A of mass 8.0 kg and block X are attached to a rope that passes over a pulley.A 50-N force P is applied horizontally to block A,keeping it in contact with a rough vertical face.The coefficients of static and kinetic friction between the wall and block A are μ_s = 0.40 and μ_k = 0.30.The pulley is light and frictionless.In the figure,the mass of block X is adjusted until block A descends at constant velocity of 4.75 cm/s when it is set into motion.What is the mass of block X?

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?

Two blocks are connected by a string that goes over an ideal pulley as shown in the figure and pulls on block A parallel to the surface of the plane.Block A has a mass of 3.00 kg and can slide along a rough plane inclined 30.0° to the horizontal.The coefficient of static friction between block A and the plane is 0.400.What mass should block B have in order to start block A sliding up the plane?

A system comprised blocks,a light frictionless pulley,and connecting ropes is shown in the figure.The 9.0-kg block is on a perfectly smooth horizontal table.The surfaces of the 12-kg block are rough,with between the block and the table.If the 5.0-kg block accelerates downward when it is released,find its acceleration.

A 20-ton truck collides with a 1500-lb car and causes a lot of damage to the car.During the collision

A system comprising blocks,a light frictionless pulley,a frictionless incline,and connecting ropes is shown in the figure.The 9.0-kg block accelerates downward when the system is released from rest.The tension in the rope connecting the 6.0-kg block and the 4.0-kg block is closest to

Consider what happens when you jump up in the air.Which of the following is the most accurate statement?

A system of blocks and a frictionless pulley is shown in the figure.Block A has a mass of 2.0 kg and is on a rough horizontal surface for which μ_s = 0.40 between the surface and block A.The rope pulls horizontally on block A.Block C has a mass of 1.0 kg.An external force P = 23.0 N,applied vertically to block A,maintains the system at rest as shown in the figure.What is the friction force on block A?

Three objects are connected as shown in the figure.The strings and frictionless 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?

Three boxes in contact rest side-by-side on a smooth,horizontal floor.Their masses are 5.0-kg,3.0-kg,and 2.0-kg,with the 3.0-kg box in the center.A force of 50 N pushes on the 5.0-kg box,which pushes against the other two boxes. (a)Draw the free-body diagrams for each of the boxes. (b)What magnitude force does the 3.0-kg box exert on the 5.0-kg box? (c)What magnitude force does the 3.0-kg box exert on the 2.0-kg box?

A 20.0-N box rests on a 50.0-N box on a perfectly smooth horizontal floor.When a horizontal 15.0-N pull to the right is exerted on the lower box (see figure),both boxes move together.Find the magnitude and direction of the net external force on the upper box.

Two objects are connected by a very light flexible string as shown in the figure,where M = 0.60 kg and m = 0.40 kg.You can ignore friction and the mass of the pulley. (a)Draw free-body diagrams for each object. (b)Calculate the magnitude of the acceleration of each object. (c)Calculate the tension in the string.

Two weights are connected by a massless wire and pulled upward with a constant speed of 1.50 m/s by a vertical pull P.The tension in the wire is T (see figure).Which one of the following relationships between T and P must be true?

A 4.00-kg box sits atop a 10.0-kg box on a horizontal table.The coefficient of kinetic friction between the two boxes and between the lower box and the table is 0.600,while the coefficient of static friction between these same surfaces is 0.800.A horizontal pull to the right is exerted on the lower box,as shown in the figure,and the boxes move together.What is the friction force on the UPPER box?