Negative work can be done
a. by friction on the tires while a car is accelerating without skidding.
b. by a spring at the bottom of an elevator shaft when it stops a falling elevator.
c. by a hand catching a ball.
d. by all of the above. e. only by (b) and (c) above.
E
You might also like to view...
A uniform ladder 15 ft long is leaning against a frictionless wall at an angle of 53° above the horizontal. The weight of the ladder is 30 pounds. A 75-lb boy climbs 6.0-ft up the ladder. What is the magnitude of the friction force exerted on the ladder by the floor?
a. 43 lb b. 34 lb c. 38 lb d. 47 lb e. 24 lb
What is the most accurate way to determine the distance to a relatively nearby star (within the Milky Way)?
A) radar ranging B) stellar parallax C) using Cepheid variables D) using white dwarf supernovae E) applying Hubble's law
A car traveling along the highway brakes to a stop over a certain distance. More braking force is required if the car has
A) more mass. B) more momentum. C) less stopping distance. D) all of the above E) none of the above
Asteroids are similar in composition, leading scientists to suspect that they formed from the breakup of a single large object, such as a planet
Indicate whether the statement is true or false