The momentum change of an object is equal to the

a. impulse acting on it

b. force acting on it times its velocity

c. velocity change of the object

d. object's mass times the force acting on it

e. force acting on it

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

If a simple machine reduces the strength of a force, what must be increased?

Aplayer uses a hockey stick to push a puck at a constant velocity across the ice. the weight of the puck is 170 n. the coefficient of friction is 0.0600. with what force must the player push the puck so that his force just equals the frictional force? 28.3 n 0.999 n 0.102 n 0.0104 n