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Questions in physics

[Done] A force of 200 N is required to keep an object sliding at a constant speed of 2 m/s across a rough floor. How much power is being expended to maintain this motion?

[Done] After a large snowstorm, you shovel 2,500 kilograms of snow off of your sidewalk in half an hour. You lift the shovel to an average height of 1.5 meters while you are piling the snow in your yard. a. How much work did you do? (Hint: The force is the weight of the snow.) b. What was your power in watts? (Hint: You must always convert time to seconds when calculating power.)

[Done] If a small machine does 2,500 joules of work on an object to move it a distance of 100 meters in 10 seconds: 1. What is the force needed to do the work? 2. What is the power of the machine doing the work?

[Done] Green light has a lower frequency than blue light. Which color of light has a longer wavelength?

[Done] In a bizarre but harmless accident, Superman fell from the top of the Eiffel Tower. How fast was Superman traveling when he hit the ground 7.80 seconds after falling?

[Done] A man on the moon with a mass of 90 kilograms weighs 146 newtons. The radius of the moon is [tex]1.74 \times 10^6[/tex] meters. Find the mass of the moon.

[Done] Two dogs pull on a toy. One pulls with a force of 10 N, the other with a force of 15 N. In what relative directions can the dogs act to give the toy the smallest acceleration?

[Done] What is the acceleration of a 6.4-kilogram bowling ball if a force of 12 N is applied to it?

[Done] A sound wave travels at 330 m/sec and has a wavelength of 2 meters. Calculate its frequency and period.

[Done] Which substance—wood or steel—is the better conductor? A conductor is a material that requires very little heat energy to experience a change in temperature. Explain your answer.