Showing 11 to 20 of 400 Questions
  • The particle P is acted upon by its weight of 3 lb and forces F1 and F2, where t is in seconds. If the particle originally has a velocity of v1 = {3i + 1j + 6k) ft/s, determine its speed after 2 s.

  • The twitch in a muscle of the arm develops a force which can be measured as a function of time as shown in the graph. If the effective contraction of the muscle lasts for a time t0, determine the impulse developed by the muscle.

  • Assuming that the force acting on a 2-g bullet, as it passes horizontally through the barrel of a rifle, varies with time in the manner shown, determine the maximum net force To, applied to the bullet when it is fired. The muzzle velocity is 500 m/s when t = 0.75 ms. Neglect friction between the bullet and the rifle barrel.

  • As indicated by the derivation, the principle of impulse and momentum is valid for observers in any inertial reference frame. Show that this is so, by considering the 10-kg block which rests on the smooth surface and is subjected to a horizontal force of 6 N. If observer A is in a fixed frame x, determine the final speed of the block in 4

  • The 4-lb cabinet is subjected to the force F =12(t + 1)^2 lb where t is in seconds. If the cabinet is initially moving up the plane with a velocity of 10 ft/s, determine how long it will take before the cabinet comes to a stop. F always acts parallel to the plane. Neglect the size of the rollers.

  • If it takes 35s for the 50-Mg tugboat to increase its speed uniformly to 25 km/h, starting from rest, determine the force of the rope on the tugboat. The propeller provides the propulsion force F winch gives the tugboat forward motion, whereas the barge moves freely. Also, determine F acting on the tugboat. The barge has a mass of 75 mg.

  • The 5.5-Mg humpback whale is stuck on the there due to changes in the tide. In an effort to rescue a whale, 12-Mg tugboat is used to pull it fee using an inextensible rope tied to its tail. To overcome the frictional force of the sand on the whale, the tug backs up so that the rope becomes slack and then the tug proceeds forward at 3 m/s.

  • The uniform beam has a weight of 5000 lb. Determine the average tension in each of the two cables AB and AC if the beam is given an upward speed of 8 ft/s in 1.5 s starting from rest. Neglect the mass of the cables.

  • The 5-kg block is moving downward at v1= 2 m/s when it is 8 m from the sandy surface. Determine the impulse of the sand on the block necessary to stop its motion. Neglect the distance the block dents into the sand and assume the block does not rebound. Neglect the weight of the block during the impact with the sand.

  • The 5-kg block is falling downward at v1 2 m/s when it is 8 m from the sandy surface, Determine the average impulsive force acting on the block by the sand if the motion of the block is stopped in 0.9 s once the block strikes the sand. Neglect the distance the block dents into the sand and assume the block does not rebound. Neglect the we