13–90. The 40-kg boy is sliding down the smooth spiral slide such that z = -2 m/s and his speed is 2 m/s. Determine the r, 0, z components of force the slide exerts on him at this instant. Neglect the size of the boy. r = 1.5 m

Repeat the preceding problem, but including a drag force due to air of fdrag=bv .

When a body slides down an inclined plane, does the work of friction depend on the body’s initial speed? Answer the same question for a body sliding down a curved surface.

A block of weight w = 40.0 N sits on a frictionless inclined plane, which makes an angle θ = 24.0∘ with respect to the horizontal, as shown in the figure. (Figure 1) A force of magnitude F = 16.3 N , applied parallel to the incline, is just sufficient to pull the block up the plane at constant speed.

An old miser with a bag og gold jums onto the surface of a frozen lake and hopes to coast civilization on the other side.Unfortunately the ice does have a coefficient of kinetic friction ?ₖ=0.08. He slides for 80 m and then stops.(Now he has to walk.) How fast was he moving at the start of his coast?

In the Skycoaster amusement park ride, riders are suspended from a tower by a long cable. A second cable then lifts them until they reach the starting position indicated is shown. The lifting cable is then released, and the riders swing down the circular arc shown. If the four riders have a total mass of 270 kg, what are the tensions in the two cables just before release?

An eraser is pushed up a chalkboard with a force of 4.0 N. The push is applied into the board and makes an angle of 27° with the board surface as shown in the figure to the right. The eraser moves up the board with constant velocity, and the coefficient of kinetic friction between the eraser and the board is 0.25. What is the mass of the eraser? 270

Suppose that down at the docks, Popeye is pulling the objects shown below with a force of 985[N] in the horizontal direction, as shown below. Mass #2 (150.0[kg]) is connected to Mass #1 (50.0[kg]) by a single cable that is passed over an ideal pulley. The coefficient of kinetic friction between Mass #2 and the ledge is 0.254. He successfully moves the objects after they were at rest.  What is the magnitude of the gravitational force on Mass #1? Express your answer in units of Newtons. What is the magnitude of the gravitational force on Mass #2? Express your answer in units of Newtons. What is the magnitude of the tension in the rope connecting the objects? Express your answer in units of Newtons. What is the magnitude of the acceleration of the objects? Express your answer in units of m/s2.

In figure (4), the crate is initially at rest on the ground. If the motor exerts a force of F = (600 + 2 s*) N on the cable. 5) What is the speed of the 10 kg crate when it rises to s = 10 m. b) 23.8 m/s f) 29.2 m/s c)59.2 m/s a) 17.2 m/s e) 49.7 m/s d) 12.5 m/s g) None of them 15 m Figure (4)