What is friction?, rate at which an object changes motion, a force that opposes motion, a force of attraction between two objects, A book is placed at the top of the ramp made from a board.  In order to cause the book to slide down the ramp, how should the ramp be changed?, make it longer, make it steeper, make it rougher, A child pushed and released a toy train set.  The train eventually slowed.  The force responsible for the train slowing was, magnetic., electrical., friction., Amanda tested toy car tires to see which would go down a ramp the most slowly.  She found that the tire that caused the most friction moved down the ramp the most slowly.  Which properties did the tires that moved the most slowly have?, round shape and smooth material, round shape and rough material, oval shape and rough material, A student is riding a bike and applies the brakes.  Which most helps the bike to stop?, momentum, friction, gravity, Why is it easy to slip when there is water on the floor?, The water reduces friction between your feet and the floor., The water increases friction between your feet and the floor., The friction between your feet and the floor changes., Which of the following does not involve any kind of friction?, A bicycle rolling down a hill., Swimming in a pool., Ice skating., All of the above experience some kind of friction., A rough surface produces more friction., True, False, A smooth surface produces less friction., True, False, When workers spread sand over icy bridges and roads in the winter, how does this help people drive on the roads?, The sand increases friction between the road and the tires of the car., The sand increases the inertia of the car., What does friction do to a piece of chalk?, It melts it., It wears it down., It would probably be easiest to ride a bicycle across, the grass., gravel., a sidewalk., sand., Which type of force requires contact between two objects for one to push or pull the other?, the force of gravity acting on raindrops that fall to Earth, frictional forces slowing down a soccer ball, Both students played on a slide.  Student 1 wore shorts, and student 2 wore long pants.  Which of these explanations best identifies why student 2 moved down the slide more smoothly than student 1?, more weight, less friction, The motion of an object is affected by friction., True, False.

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