A student attaches a rope to a 9.5 kg box of books. He pulls with a force of 45 N at an angle of 30° with the horizontal. The coefficient of kinetic friction between the box and the sidewalk is 0.29. Find the acceleration of the box. PLEASE SOME ONE HELP

What if? physicists often measure the momentum of subatomic particles moving near the speed of light in units of mev/c, where c is the speed of light, and 1 mev = 1.6 ✕ 10−13 kg · m2/s2. based on this, what are the units of momentum for a high-speed subatomic particle in terms of fundamental si units?

28. a stone is projected at a cliff of height h with an initial speed of 42.0 mls directed at angle θ0 = 60.0° above the horizontal. the stone strikes at a, 5.50 s after launching. find (a) the height h of the cliff, (b) the speed of the stone just before impact at a, and (c) the maximum height h reached above the grou

Acar moves a distance of 50.0 km west, followed by a distance of 64.9 km north what was the magnitude of the displacement of the car, in units of kilometers?