A locomotive pulls 10 identical freight cars of mass m = 1.0 × 10° kg with an acceleration of a = 5.0 m/s². What is the magnitude F45 of the force between the fourth and fifth cars? F45 What is the magnitude F78 of the force between the seventh and eighth cars? F1,8

A car accelerates down a hill (Fig. P4.57), going from rest to 30.0 m/s in 6.00 s. A toy inside the car hangs by a string from the cars ceiling. The ball in the figure represents the toy, of mass 0.100 kg. The acceleration is such that the string remains perpendicular to the ceiling. Determine (a) the angle and (b) the tension in the string. Figure P4.57

A crate remains stationary after it has been placed on a ramp inclined at an angle with the horizontal. Which of the following statements must be true about the magnitude of the frictional force that acts on the crate? (a) It is larger than the weight of the crate. (b) It is at least equal to the weight of the crate. (c) It is equal to sn. (d) It is greater than the component of the gravitational force acting down the ramp. (e) It is equal to the component of the gravitational force acting down the ramp.

A hockey stick pushes a 0.160-kg puck with constant force across the frictionless surface of an ice rink. During this motion, the pucks velocity changes from 4.00 m/s to (6.00 + 12.00) m/s in 4.00 s. a. What are the scalar components of the force acting on the puck? b. What is the magnitude of the force acting on the puck?

A black widow spider hangs motionless from a web that extends vertically from the ceiling above. If the spider has a mass of 1.5 g, what is the tension in the web?

Two blocks, each of mass m, are hung from the ceiling of an elevator as in Figure P4.33. The elevator has an upward acceleration a. The strings have negligible mass. (a) Find the tensions T1 and T2 in the upper and lower strings in terms of m, a, and g. (b) Compare the two tensions and determine which string would break first if a is made sufficiently large. (c) What are the tensions if the cable supporting the elevator breaks? Figure P4.33 Problems 33 and 34.

A 1.00 103 car is pulling a 300.-kg trailer. Together, the car and trailer have an acceleration of 2.15 m/s2 in the positive x-direction. Neglecting frictional forces on the trailer, determine (a) the net force on the car, (b) the net force on the trailer, (c) the magnitude and direction of the force exerted by the trailer on the car, and (d) the resultant force exerted by the car on the road.

A sleigh is being pulled horizontally by a train of horses at a constant speed of 8.05 m/s. The magnitude of the normal force exerted by the snow-covered ground on the sleigh is 6.37 103 N. a. If the coefficient of kinetic friction between the sleigh and the ground is 0.23, what is the magnitude of the kinetic friction force experienced by the sleigh? b. If the only other horizontal force exerted on the sleigh is due to the horses pulling the sleigh, what must be the magnitude of this force?

Two objects, A and B, are connected by a rigid rod that has a length L. The objects slide along perpendicular guide rails, as shown in Figure P2.57. If A slides to the left with a constant speed v, find the velocity of B when α = 60.0°. Figure P2.57

An object of mass m1 hangs from a string that passes over a very light fixed pulley P1 as shown in Figure P4.40. The string connects to a second very light pulley P2. A second string passes around this pulley with one end attached to a wall and the other to an object of mass m2 on a frictionless, horizontal table. (a) If a1 and a2 are the accelerations of m1 and m2, respectively, what is the relation between these accelerations? Find expressions for (b) the tensions in the strings and (c) the accelerations a1 and a2 in terms of the masses m1 and m2, and g. Figure P4.40