Reading Quiz 11/12

A 35-N bucket of water is lifted vertically 3.0 m and then returned to its original position. How much work did gravity do on the bucket during this process?

0 J

A force produces power P by doing work W in a time T. What power will be produced by a force that does six times as much work in half as much time?

12P

Which requires more work, increasing a car's speed from 0 mph to 30 mph or from 50 mph to 60 mph?

50 mph to 60 mph

A heavy dart and a light dart are launched horizontally on a frictionless table by identical ideal springs. Both springs were initially compressed by the same amount. Which of the following statements about these darts are correct? (There could be more than one correct choice.)

A, B, E -the darts both have the same kinetic energy just as they move free of the spring -the lighter dart leaves the spring moving faster than the heavy dart -both darts had the same initial elastic potential energy

A heavy dart and a light dart are launched vertically by identical ideal springs. Both springs were initially compressed by the same amount. There is no significant air resistance. Which of the following statements is correct?

B, D -the light dart goes higher than the heavy dart -at the maximum height, both darts have the same gravitational potential energy

You and your friend, who weighs the same as you, want to go to the top of the Eiffel Tower. Your friend takes the elevator straight up. You decide to walk up the spiral staircase, taking longer to do so. Compare the gravitational potential energy of you and your friend, after you both reach the top.

Both of you have the same amount of gravitational potential energy at the top.

Three cars (car L, car M, and car N) are moving with the same speed and slam on their brakes. The most massive car is car L, and the least massive is car N. If the tires of all three cars have identical coefficients of kinetic friction with the road surface, for which car is the amount of work done by friction in stopping is the greatest?

Car L

The graphs shown show the magnitude F of the force exerted by a spring as a function of the distance x the spring has been stretched. For which one of the graphs does the spring obey Hooke's law?

Graph b

Three cars (car F, car G, and car H) are moving with the same speed and slam on their brakes. The most massive car is car F, and the least massive is car H. If the tires of all three cars have identical coefficients of kinetic friction with the road surface, which car travels the longest distance to skid to a stop?

They all travel at the same distance in stopping.

Two objects, one of mass m and the other of mass 2m, are dropped from the top of a building. If there is no air resistance, when they hit the ground

the heavier one will have twice the kinetic energy of the lighter one