A 30-lb block is initially moving along a smooth horizontal surface with a speed of v1 = 6 ft/s to the left. If it is acted upon by a force F, which varies in the manner shown, determine the velocity of the block in 15 s. The argument for the cosine is in radians.

A 30-lb block is initially moving along a smooth horizontal surface wi

1.	A 30-lb block is initially moving along a smooth horizontal surface with a speed of v1 = 6 ft/s to the left. If it is acted upon by a force F, which varies in the manner shown, determine the velocity of the block in 15 s. The argument for the cosine is in radians.
A.	v2 = 91.4 ft/s 7
B.	v2 = 79.4 ft/s 6
C.	v2 = 91.4 ft/s 6
D.	v2 = 79.4 ft/s 7
Answer» B. v2 = 79.4 ft/s 6

Discussion

No Comment Found

Related MCQs

The uniform rod AB has a weight of 3 lb and is released from rest without rotating from the position shown. As it falls, the end A strikes a hook S, which provides a permanent connection. Determine the speed at which the other end B strikes the wall at C.
The uniform pole has a mass of 15 kg and falls from rest when = 90° until it strikes the edge at A, = 60°. If the pole then begins to pivot about this point after contact, determine the pole's angular velocity just after the impact. Assume that the pole does not slip at B as it falls until it strikes A.
The square plate, where a = 0.75 ft, has a weight of 4 lb and is rotating on the smooth surface with a constant angular velocity of 1 = 10 rad/s. Determine the new angular velocity of the plate just after its corner strikes the peg P and the plate to rotate about P without rebounding.
A horizontal circular platform has a weight of 300 lb and a radius of gyration about the z axis passing through its center O of kz = 8 ft. The platform is free to rotate about the z axis and is initially at rest. A man, having a weight of 150 lb, begins to run along the edge in a circular path of radius 10 ft. If he has a speed of 4 ft/s and maintains this speed relative to the platform, compute the angular velocity of the platform.
The 50-kg cylinder has an angular velocity of 30 rad/s when it is brought into contact with the horizontal surface at C. If the coefficient of friction is c = 0.2, determine how long it takes for the cylinder to stop spinning. What force is developed at the pin A during this time? The axis of the cylinder is connected to two symmetrical links. (Only AB is shown.) For the computation, neglect the weight of the links.
The flywheel A has a mass of 30 kg and a radius of gyration of kc = 95 mm. Disk B has a mass of 25 kg, is pinned at D, and is coupled to the flywheel using a belt which is subjected to a tension such that it does not slip at its contacting surfaces. If a motor supplies a counter-clockwise torque or twist to the flywheel, having a magnitude of M = (12t) N m, where t is measured in seconds, determine the angular velocity of the disk 3 s after the motor is turned on. Initially, the flywheel is at rest.
The 12-kg disk has an angular velocity of = 20 rad/s. If the brake ABC is applied such that the magnitude of force P varies with time as shown, determine the time needed to stop the disk. The coefficient of friction at B is = 0.4.
Gear A has a weight of 1.5 lb, a radius of 0.2 ft, and a radius of gyration of ko = 0.13ft. The coefficient of friction between the gear rack B and the horizontal surface is = 0.3. If the rack has a weight of 0.8 lb and is initially sliding to the left with a velocity of (vB)2 = 8 ft/s to the left. Neglect friction between the rack and the gear and assume that the gear exerts only a horizontal force on the rack.
A constant torque or twist of M = 0.4N m is applied to the center gear A. If the system starts from rest, determine the angular velocity of each of the three (equal) smaller gears in 3 s. The smaller gears (B) are pinned at their centers, and the mass and centroidal radii of gyration of the gears are given in the figure.
A cord of negligible mass is wrapped around the outer surface of the 2-kg disk. If the disk is released from rest, determine its angular velocity in 3 s.

A 30-lb block is initially moving along a smooth horizontal surface with a speed of v1 = 6 ft/s to the left. If it is acted upon by a force F, which varies in the manner shown, determine the velocity of the block in 15 s. The argument for the cosine is in radians.

Discussion

No Comment Found

Related MCQs

Reply to Comment