Chapter 15, Problem 34P

The force P is applied to the 50-kg block when it is at rest. Determine the magnitude and direction of the friction force exerted by the surface on the block if (a) P = 0, (b) P = 226 N, and (c) P = 353 N. (d) What value of P is required to initiate motion up the incline? The static and kinetic coefficients of friction between the block and the incline are μs = 0.30 and μk = 0.27, respectively. The friction force is positive if up the incline, negative if down the incline.

The illustration in Fig. 3 shows the 20-kg block A sliding down on a rough surface with a slope of 15°. The dynamic coefficient of friction between the block's contact surface and the supporting surface is HA = 0.2. At the beginning of the experiment (t = 0s), the block A has a velocity of v = 15 m/s and the distance between A and the 15-kg block B is s = 6 m. The spring has a stiffness of k = 2000 N/m. Determine the maximum compression of the spring due to the collision. Assume ug = 0.3 for the sliding of B and e = 0.5 for the 5. Collision. collision. 15 m/s -k = 2000 N/m s = 6 m 15°

The force P is applied to the 38-kg block when it is at rest. Determine the magnitude and direction of the friction force exerted by the surface on the block if (a) P = 0, (b) P = 143 N, and (c) P = 208 N. (d) What value of P is required to initiate motion up the incline? The static and kinetic coefficients of friction between the block and the incline are μs = 0.23 and μk = 0.20, respectively. The friction force is positive if up the incline, negative if down the incline.

The force P is applied to the 48-kg block when it is at rest. Determine the magnitude and direction of the friction force exerted by the surface on the block if (a) P = 0, (b) P = 229 N, and (c) P = 354 N. (d) What value of P is required to initiate motion up the incline? The static and kinetic coefficients of friction between the block and the incline are μs = 0.34 and μk = 0.30, respectively. The friction force is positive if up the incline, negative if down the incline.

Question 17 The 3-kg disk Dis attached to the end of a cord. The other end is attached to ball and socket joint located at the center of platform. If the platform is rotating rapidly, and the disk is placed on it and released from rest, determine the time it takes for the disk to reach a speed great enough to break the cord. The max tension the cord can sustain is 100 N, and the coefficient of kinetic friction between disk and platform is Pk= 0.1 -- Motion of platfom Question 18 Design of the ski requires knowing the type of forces that will be exerted on the skier and his approximate trajectory. In the case as shown, determine the normal force and acceleration on the 600-N skier the instant he arrives at the end of jump, A, where his velocity is 9 m/s. 15 m Question 19 Packages, each of mass 2-kg, are delivered from a conveyor to a smooth circular ramp with a velocity of vo= 1 m/s. If the effective radius of the ramp is 0.5 m, determine the angle 0= Omax at which each package begins…

The force P is applied to the 52-kg block when it is at rest. Determine the magnitude and direction of the friction force exerted by the surface on the block if (a) P = 0, (b) P = 245 N, and (c) P = 361 N. (d) What value of P is required to initiate motion up the incline? The static and kinetic coefficients of friction between the block and the incline are μs = 0.28 and μk = 0.23, respectively. The friction force is positive if up the incline, negative if down the incline.

The force P is applied to the 61-kg block when it is at rest. Determine the magnitude and direction of the friction force exerted by the surface on the block if (a) P = 0, (b) P = 258 N, and (c) P = 449 N. (d) What value of P is required to initiate motion up the incline? The static and kinetic coefficients of friction between the block and the incline are Ng = 0.31 and ug = 0.28, respectively. The friction force is positive if up the incline, negative if down the incline. 61 kg 29 H,= 0.31 H= 0.28 19 The tolerance is ± 1 in the 3rd significant digit. (a) F= i N (b) F= i (c) F= i (d) P= i N

The force P is applied to the 61-kg block when it is at rest. Determine the magnitude and direction of the friction force exerted by the surface on the block if (a) P = 0, (b) P = 188 N, and (c) P = 268 N. (d) What value of P is required to initiate motion up the incline? The static and kinetic coefficients of friction between the block and the incline are ug = 0.18 and µ = 0.15, respectively. The friction force is positive if up the incline, negative if down the incline. P 61 kg 17° H= 0.18 HE = 0.15 11 Answers: (a) F= N (b) F = i N (c) F = i (d) P= i N

HW5 The arms of a Porter governor are 300 mm long. The upper arms are pivoted on the axis of rotation. The lower arms are attached to a sleeve at a distance of 40 mm from the axis of rotation. The mass of the load on the sleeve is 70 kg and the mass of each ball is 10 kg. Determine the equilibrium speed when the radius of rotation of the balls is 200 mm. If the friction is equivalent to a load of 20 N at the sleeve, what will be the range of speed for this position and Sensitiveness of Governors?