If the distance from earth to alpha centauri is 4.34 light-years, then a) alpha centauri is the closest star to earth. b) we see alpha centauri as it was four years ago. c) the distance is equal to 4.34 astronomical units. d) alpha centauri is four times farther from earth than the sun.

Abird flies directly overhead from where you stand at an altitude of 300.0 m and at a speed horizontal to the ground of 20.0 m/s. the bird has a mass of 2.0 kg. the radius vector to the bird makes an angle \thetaθ with respect to the ground. the radius vector to the bird and its momentum vector lie in the xyxy-plane. what is the bird’s angular momentum about the point where you are standing?

Does heating a metal wire increase or decrease its electrical resistance? why?

Emagnitude of the electrical force acting between a +2.4 ×  10–8  c charge and a +1.8 ×  10–6  c charge that are separated by 0.008 m is    n, rounded to the tenths place.