Abox slides on an inclined plane (=40°) that has friction (=0.43) which causes the box to slide with a constant velocity of 3 m/s. the box reaches the bottom and continues to slide across a horizontal surface with friction (=0.34) until coming to rest five meters from the base of the ramp. what is the length of the ramp that the box slid down?

the answer is that the length of the ramp is 4m, but i don't see how to get there. since the box is sliding down the ramp at a constant speed, there is no net force acting on the box, which means the net work done on the ramp is zero. the energy the box has at the bottom of the ramp doesn't equal the work done to travel 5 meters from the bottom of the ramp.

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What is the kinetic energy of a 10-kg bicycle moving at 10 m/s

1. in terms of fuel economy rank the following hybrid and electric vehicles, and justify application specific to each hybrid technology stop/start | mild hybrid | full hybrid | plug-in hybrid | full electric a. rank based on fuel economy b. justify your application specific for each technology

Comedians like to joke that the reason we haven’t been visited by intelligent life from elsewhere in the universe is that aliens have been monitoring earth’s broadcasts of intellectually embarrassing tv programs, like gilligan’s island, fear factor, the jersey shore, and the jerry springer showand so consider us far too primitive to merit a visit. let’s check the assertion that aliens could have been receiving them. tv programs are broadcast at a frequency of about 100mhz with about 100kw of total power in 30frames per second, which emanatesroughly uniformly in all directions. assume that interstellar space transmits these broadcasts without attenuation. no matter how smart they are, aliens would require at least one photon per frame to interpret our signals. findthe number of photons per unit time per unit area reaching a receiver on a possible planet in the nearest star system, which is about 4 light-years away (a light-year is the distance light travels in a year). if aliens aimed a receiver or detector directly at earth, how big (in diameter) would it have to be to receive a photon per frame