An atom is electrically neutral because

Suppose that 27 j of work is needed to stretch a spring from its natural length of 6 m to a length of 9 m. (a) how much work is needed to stretch the spring from 12 m to 14 m? j (b) how far beyond its natural length will a force of 78 n keep the spring stretched?

Ahorizontal force of 400.0 n is required to pull a 1760 n truck across the floor at a constant speed. find the coefficient of sliding friction.

Would it be correct to say the doppler effect is the apparent change in the speed of a wave due to the motion of the source? be sure to fully explain your position using at least 3 complete content related sentences.