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Question 1 (1 point] Which requires more work: lifting a 7-kg rock to a height of 1.8 m without acceleration or accelerating the same rock horizontally from rest to a speed of 6 me? If j Both cases require the same amount of work {"i} Lifting the rock without acceleration requires more work. If i} Accelerating the rock horizontally from rest to a speed requires more work. Question 2 (1 point} A rope applies a horizontal force of 220 N to pull a crate a distance of 45 m across the floor. A frictional force of 110 N opposes this motion. What is the work done by the force applied by the rope in units of J? (ii3210 (:11230 (ii2310 (i11320 Question 3 (1 point) A ball is being twirled in a circle at the end of a string. The string provides the centripetal force needed to keep the ball moving in a circle at constant speed. What is the sign of the work done by the string on the ball in this situation? .f f}. positive .f :3. negative .f f}. zero, the string does no work Question 4 (1 point) A child and sled with mass of 46.4 kg slide down a hill with a height of 4.17 m. If the sled starts from rest and has a speed of 4.6 m/s at the bottom, how much thermal energy in units of joules is lost due to friction. (This will be the work done.) (use g=9.8 m/s2 and be accurate to 2 decimals) Your Answer: AnswerConsider the three different frictionless ramps shown below. You push an identical box up each ramp at a constant speed of 3.1 m/s. What is the work done by the Normal force in units OH and to 1 decimal point? Your Answer: 0.0 Answer Question 6 (1 point) A 57.0 kg woman runs up a flight of stairs in 5 s. Her net upward displacement is 5 m. What power did the woman exert while she was running (in units of W and to 2 decimals using g=9.81 m/s2)? Your Answer: Answer Question 7 (1 point) In a circus a spring loaded cannon is used to shoot a human cannonball (with a mass of 54.5 kg) over a net that is 7.5 m high. The spring in the cannon has a spring constant of 780 N/m and is compressed 4.5 m. As the human cannonball just clears the net, he is moving at a speed of 3.3 m/s. How much energy (in units of J) was dissipated by air resistance as the person just cleared the net? (use g=9.81 m/s2 , round to exact number and use - sign if answer is negative) Your Answer: AnswerQuestion 8 {1 point) In which of the following systems is the work done by a frictional force resulting in the increase of the total mechanical energy of a system? O a carwith positive acceleration 0 none O a skidding car with negative acceleration Question 9 {1 point) A pendulum is pulled back from its equilibrium (center) position and then released. When the bob is halfway between the high point and the low point in its swing in what formlIs} is the total energy of the bob? 0 kinetic only 0 partially kinetic, partially potential O potential only Question 10 {1 point} woman uses a pulley arrangement to lift a heavy crate. She applies a force that is oneforth the weight of the crate. but moves the rope a distance four times the height that the crate is lifted. How does the work clone by the woman on the rope compare to the work clone by the rope on the create if there are no dissipative forces? 0 the work clone by the woman is greater 0 the work clone by the woman is equal 0 the work clone by the woman is less