Exam 7: Newtons Third Law

A 4.00-kg block rests between the floor and a 3.00-kg block as shown in the figure.The 3.00-kg block is tied to a wall by a horizontal rope.If the coefficient of static friction is 0.800 between each pair of surfaces in contact,what horizontal force F must be applied to the 4.00-kg block to make it move?

The International Space Station has a mass of 1.8 × 10⁵ kg.A 70.0-kg astronaut inside the station pushes off one wall of the station so she accelerates at 1.50 m/s².What is the magnitude of the acceleration of the space station as the astronaut is pushing off the wall? Give your answer relative to an observer who is space walking and therefore does not accelerate with the space station due to the push.

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 mass M?

A pickup truck is moving at 25 m/s with a toolbox of mass m resting on the bed of the truck 2.5 m behind the cab.Suddenly the brakes are applied,causing the toolbox to slide,and the truck comes to a stop in 4.7 s.The coefficient of kinetic friction between the toolbox and the bed of the truck is 0.28.After the brakes are applied,how much time elapses before the toolbox strikes the cab?

In the figure,two wooden blocks each of 0.30 kg mass are connected by a string that passes over a very light frictionless pulley.One block slides on a horizontal table,while the other hangs suspended by the string,as shown in the figure.At time t = 0,the suspended block is 0.80 m over the floor,and the blocks are released from rest.After 2.5 s,the suspended block reaches the floor.What is the coefficient of kinetic friction between the table and the sliding block?

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 2.3 m/s² by force .What is the tension at the top end of rope 1?

A locomotive is pulling 19 freight cars,each of which is loaded with the same amount of weight.The mass of each freight car (with its load)is 37,000 kg.If the train is accelerating at on a level track,what is the tension in the coupling between the second and third cars? (The car nearest the locomotive is counted as the first car,and friction is negligible.)

A wooden block A of mass 4.0 kg slides on a frictionless table when pulled using 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.

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.The pulley has no appreciable mass or friction.What is the acceleration of the 2.0 kg block?

In order to lift a bucket of concrete,you must pull up harder on the bucket than it pulls down on you.

Block A of mass 5.0 kg and block X are attached to a rope which passes over a pulley,as shown in the figure.An 80-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.The mass of block X is adjusted until block A moves upward with an acceleration of 1.6 m/s².What is the mass of block X?

The figure shows a 100-kg block being released from rest from a height of 1.0 m.It then takes it 0.90 s to reach the floor.What is the mass m of the other block? The pulley has no appreciable mass or friction.

A 6.00-kg block is in contact with a 4.00-kg block on a horizontal frictionless surface as shown in the figure.The 6.00-kg block is being pushed by a horizontal 20.0-N force as shown.What is the magnitude of the force that the 6.00-kg block exerts on the 4.00-kg block?

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).P is closest to

Two boxes are connected by a weightless cord running over a very light frictionless pulley as shown in the figure.Box A,of mass 8.0 kg,is initially at rest on the top of the table.The coefficient of kinetic friction between box A and the table is 0.10.Box B has a mass of 15.0 kg,and the system begins to move just after it is released. (a)Draw the free-body diagrams for each of the boxes,identifying all of the forces acting on each one. (b)Calculate the acceleration of each box. (c)What is the tension in the cord?

The figure shows two packages that start sliding down a 20° ramp from rest a distance along the ramp from the bottom.Package A has a mass of 5.0 kg and a coefficient of kinetic friction 0.20 between it and the ramp.Package B has a mass of 10 kg and a coefficient of kinetic friction 0.15 between it and the ramp.How long does it take package A to reach the bottom?

Two blocks are connected by a string that goes over an ideal pulley as shown in the figure.Block A has a mass of 3.00 kg and can slide over a rough plane inclined 30.0° to the horizontal.The coefficient of kinetic friction between block A and the plane is 0.400.Block B has a mass of 2.77 kg.What is the acceleration of the blocks?

Two objects having masses m₁ and m₂ are connected to each other as shown in the figure and are released from rest.There is no friction on the table surface or in the pulley.The masses of the pulley and the string connecting the objects are completely negligible.What must be true about the tension T in the string just after the objects are released?

Two bodies P and Q on a smooth horizontal surface are connected by a light cord.The mass of P is greater than that of Q.A horizontal force (of magnitude F)is applied to Q as shown in the figure,accelerating the bodies to the right.The magnitude of the force exerted by the connecting cord on body P will be

A 1520-N crate is to be held in place on a ramp that rises at 30.0° above the horizontal (see figure).The massless rope attached to the crate makes a 22.0° angle above the surface of the ramp.The coefficients of friction between the crate and the surface of the ramp are µ_k = 0.450 and µ_s = 0.650.The pulley has no appreciable mass or friction.What is the MAXIMUM weight w that can be used to hold this crate stationary on the ramp?