Which statement best explains why the overall charge on an atom is zero?

a: the positive charge of the neutrons in the nucleus equals the negative charge in the electron cloud.
b: the positive charge of the protons in the nucleus equals the negative charge in the electron cloud.
c: the negative charge of the neutrons in the nucleus equals the positive charge in the electron cloud.
d: the negative charge of the protons in the nucleus equals the positive charge in the electron cloud.

Astudent pushes a 60-n block across the floor for a distance of 10 m. how much work was done to move the block

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?

Four friends, a, b, c, and d are standing varying distances away from a speaker which is producing sound waves.