What is the mass in mev and in kg (both to decimal places) of an electron whose speed is half the speed of light? mass in mey- mass in kg- b. what is the momentum of this electron, in kg. s-. and in mev (both in 3 decimal places)? momentum of this electron, in kg·s-1= momentum in mev/c c. what would be the energy (in ey) of a photon with the same speed energy of photon in ev-

The base of a 50-meter tower is at the origin; the base of a 50-meter tree is at (0, 50, 0). the ground is flat and the z-axis points upward. the following parametric equations describe the motion of six projectiles each launched at time t = 0 in seconds. (i) r (t) = (50 + t2)k (ii) r (t) = 2t2 j + 2t2k (iii) r (t) = 50 i + 50 j + (50 − t2)k (iv) r (t) = 2t j + (50 − t2)k (v) r (t) = (50 − 2t) i + 2t j + (50 − t)k (vi) r (t) = t i + t j + tk (a) which projectile is launched from the top of the tower and goes downward? at time t = , the projectile hits the ground at point (x, y, z) = . (b) which projectile hits the top of the tree?