Question

Sample Class Problems-Force and Acceleration Prob#l: Two people are pushing a stalled car (the mass of the car is 1850kg). One person applies a force to the car, while the other applies a force of 395N. Both forces act in the same of 560N also acts on the car, but in a direction opposite force arises because of friction and the extent to which the pavement opposes Find the acceleration of the car. direction. A third force to that in which the people are pushing. This the motion of the tires a- +0.059 m/s] Prob #2: A 15.0kg block moves on a flat, friction-free, horizontal surface. At a particular instant, two forces, F, and F, begin acting on the block. F, has a magnitude of 35.0N and acts at an angle of 60.0° with respect to the +x axis, while F, has a magnitude of 10.0N and acts along the +x axis a) Find the x and y components of the resulting acceleration. [a,- +1.83 m/s; a,- +2.02 m/'s'] b) At the instant the forces began acting on the block, it had a velocity of 20.0 m/s directed along the +x axis. Determine the displacement components of the block after 8.00s has elapsed. x+219 m;y +64.6 m] the mass of a spacecraft is m,-11,000 kg and that the mass of an astronaut is m,-92 kg. astronaut pushes on the outside of the spacecraft,exerting a force of F the accelerations of the spacecraft and the astronaut +36N on the spacecraft. Find a,- +0.0033 m/s, a0.39 m/s] standon topofa man shead. The woman weighs 490 #4: In a circus balancing act, a woman performs a hea N, and the man's head and neck weigh 50N. It is primarily the seventh cervical vertebra in the spine that supports all the weight above the shoulders. What is the normal force that this vertebra exerts on the neck and head of the man a) before the act, and b) during the act? FN-50 N] F-540 N] Prob#5: Two blocks with masses, m,-2.5 kg and m, 3.5 kg, rest on a frictionless surface and are connected by a "light" (i.e., massless) string [m, is to the right of m]. A horizontal force, F of 12.0 N pulls m, to the right. a) What is the magnitude of the acceleration of the two masses (i.e., of the system)? [2.0 m/s') b) What is the tension in the string? Prob #6: A sled, traveling at 4.00 m/s, enters a horizontal stretch of snow. The coefficient of kinetic friction is x 16.3 m] a) How far does the sled go before stopping? b) A-0.0500. coefficient of static friction is ,-0.350, and the sled and its rider have a total mass of the horizontal force needed to get the sled barely moving again after it has 38.0kg. Determine stopped 130 N Page 1 of 4 Prob #7: During ng recuperation from a neck injury, the cervical vertebrae are kept under traction device. The device creates tension in the vertebrae by pulling to the left on the head with T, which in effect, is applied to the first vertebra at the top of the spine. This vertebra remain equilibrium, because it is simultaneously pulled to the right by a force F that is supplied by the n vertebra in line. The force F comes about in reaction to the pulling effect of force T,in Newton's third law. If it is desired that F have a magnitude of 34 N, how much mass m should be tension by suspended from the rope? m-3.5 kgl Free-body dagm b) 1a) For the traction device shown, the weight of the 2.2 kg mass creates a tension in the rope that passes around the pulleys. Therefore, tension forces T, and T, are applied to the pulley on the foot, and they have the same magnitude T. The foot pulley is kept in equilibrium, because the foot also applies a force to it. This force arises in reaction (Newton's 3d Law) to the pulling effect of the forces T, and T Ignoring the weight of the foot, find the magnitude of IF F-36 N] Ti cos 35* 35* 12 1b) Free-body Cagn An automobile engine has a weight W, whose magnitude is 3150 N. This engine is being positioned above an engine compartment. To position the engine, a worker is using a rope. Find the tension T, in the supporting cable and the tension T, in the positioning rope. Prob#9: 100* ing IT-3.30x10' N T,-582 N] Page 2 of 4

Answer 1

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