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A force of attraction between objects due to their masses and the distances between them is _______ air resistance Kinetic energy Friction Gravity A type of friction with air molecules as an object falls is ___________ speed mass air resistance gravity The hammer and the feather stayed where they were. 6.11b In 1971, the Apollo 15 spacecraft landed on the moon. During this mission, astronaut David Scott wanted to see what would happen if he dropped a hammer and a feather from the same height while standing on the moon’s surface. He performed the experiment, dropping both objects at the same time. What happened? The hammer hit the ground as the feather floated away The hammer and the feather hit the ground at the same time. The hammer hit the ground first and then the feather hit. Objects with greater masses have a ______________ force of attraction decreased less Greater equal Your roller coaster had the greatest Kinetic energy _____________________ near the bottom of the highest hill halfway down the hill at the end of all the hills at the top of the highest hill _____________ is a measure of gravitational pull friction weight air resistance potential energy 6.8a Which statement best describes the energy changes that occur while a child is riding on a sled down a steep, snow-covered hill? A. Kinetic energy decreases and potential energy increases. B. Kinetic energy increases and potential energy decreases. C. Both potential energy and kinetic energy decrease. D. Both potential energy and kinetic energy increase. A B C D 6.8aA cart at the top of a hill is released and rolls down the hill. Which of the followingdescribes the energy of the cart just as it reaches the bottom of the hill? A. The cart has no energy. B. The cart has maximum kinetic energy. C. The cart has maximum gravitational potential energy. D. The cart has equal gravitational potential and kinetic energy. A B C D 6.8c An escalator at a shopping mall is 40 m long and moves at a constant speed of 2 m/s. If a student steps onto the escalator at the bottom while it is moving, how long will it take him to travel the 40 m? A. 5 s B. 10 s C. 15 s D. 20 s A B C D The force of attraction between two objects depends on a Japanese sandwich the air resistance their weights mass and distance put the paper on top the tennis ball crumple the paper into a shape like the tennis ball fold the paper How might a student get a tennis ball anda piece of paper to hit the ground at the same time when dropped? A force can be a _______ or a _______.' A) spin, rotateB) push, pullC) balance point, counterbalanceD) wheel, axle A B C D ________ is a force on earth that is caused by two things rubbing together. A) motionB) spinningC) frictionD) inertia A B C D We know that _______ is what makes an object stay sitting still or keep moving until a force acts upon it. A) counterweightB) forceC) inertiaD) friction A B C D Friction is present whenever surfaces _________ A) break openB) look like simple machinesC) are smoothD) touch A B C D Which object has the most potential energy? A) Mr. Murray falling from an 8ft. ladderB) Mr. Murray falling from the 4ft. deskC) Mr. Murray standing on a 4 ft. deskD) Mr. Murray standing on an 8 ft. ladder A B C D Which force slows down a basketball rolling along the ground the most? A) solar energy B) air resistance C) friction D) gravity A B C D If my car takes 0.2558 seconds to go 30 centimeters, what is its speed in cm/second? 0.00852 cm/sec 7.674 cm/sec none of these 117.28 cm/sec |