An object has weight of 399 newtons on the surface of Venus. The acceleration due to gravity on venus is 8.87 meters per second squared. What is the mass of the object? 0.022kg
81.4 kg
41.0 kg
45.0 kg

Trumpeter a holds a b-flat note on the trumpet for a long time. person c is running towards the trumpeter at a constant velocity. person b is running away from the trumpeter at the same rate. person d is standing still the whole time. which person hears a frequency that is lower than the b-flat?

Aplanet of mass m 6.75 x 1024 kg is orbiting in a circular path a star of mass m 2.75 x 1029 kg. the radius of the orbit is r 8.05 x107 km. what is the orbital period (in earth days) of the planet tplanet?

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