Download Newton`s Third Law of Motion: Action and Reaction

Newtonʹs Third Law of Motion: Action and Reaction 1) Wherever the is an action force, there must be a reaction force which A) always acts in the same direction. B) is slightly smaller in magnitude than the action force. C) is slightly larger in amplitude than the action force. D) is exactly equal in magnitude. Answer: D 2) A player catches a ball. Consider the action force to be the impact of the ball against the playerʹs glove. The reaction to this force is the A) playerʹs grip on the glove. B) force the glove exerts on the ball. C) friction of the ground against the playerʹs shoes. D) muscular effort in the playerʹs arms. E) none of these Answer: B 3) A baseball player bats a ball with a force of 1000 N. The reaction force that the ball exerts against the bat is A) less than 1000 N. B) more than 1000 N. C) 1000 N. D) impossible to determine. Answer: C 4) A person is attracted toward the center of the Earth by a 500-N gravitational force. The Earth is attracted toward the person with a force of A) zero. B) 250 N. C) 500 N. D) 1000 N. Answer: C 5) Arnold Strongman and Suzie Small each pull very hard on opposite ends of a massless rope in a tug-of-war. The greater force on the rope is exerted by A) Arnold, of course. B) Suzie, surprisingly. C) both the same, interestingly enough. Answer: C 6) The attraction of a personʹs body toward the Earth is called weight. The reaction to this force is A) the personʹs body pushing against the Earthʹs surface. B) the Earthʹs surface pushing against the personʹs body. C) the personʹs body pulling on the Earth. D) none of these. Answer: C 7) A automobile and a baby carriage traveling at the same speed collide head-on. The impact force is A) greater on the automobile. B) greater on the baby carriage. C) the same for both. Answer: C 8) A 10.0 N force is pulling up on the ring of spring scale that weighs 2.0 N. If an 8.0 N mass is attached to the bottom hook of the scale, the scale reading would be A) 0 N. B) 2.0 N. C) 8.0 N. D) 10.0 N E) 12.0 N Answer: C
9) The force exerted by the road on each tire of an accelerating car A) equals the combined force of all four tires on the road. B) is less than the combined force of all four tires on the road. C) is more than the combined force on all four tires on the road. Answer: B 10) A piece of rope is pulled by two people in a tug-of-war. Each pulls with 400 N of force. What is the tension in the rope? A) zero B) 400 N C) 600 N D) 800 N E) none of these Answer: B 11) Two people, one twice as massive as the other, attempt a tug-of- war with 12 meters of massless rope on frictionless ice. After a brief time, they meet. The heavier person slides a distance of A) 3 m. B) 4 m. C) 6 m. D) 0 m. Answer: B 12) A bird sitting on the limb of a tree is moving about 30 km/s with respect to the sun. If the bird takes 1 second to drop down to a worm below, the worm would be 30 km downrange from the bird when it reached the ground. This faulty reasoning is best countered with Newtonʹs A) first law. B) second law. C) third law. D) law of gravitation. E) none of these. Answer: A 13) A vehicle that weighs 4000 N on the surface of the Earth is travelling in outer space at a speed of 200 m/s. The smallest constant force that must be applied to stop it in 20 seconds is A) 20 N. B) 40 N. C) 400 N. D) 4000 N. E) more than 4000 N. Answer: D