A 0.5 kg ball is at rest at the top of a 20 meter tall hill. A) What is the ball's kinetic energy?
B) What is the ball's mechanical energy

When a book falls from a shelf to the ground without anyone pushing on it, no work is done on the book. true or false

Aparticle's position is given by x = 3.00 - 9.00t + 3t2, in which x is in meters and t is in seconds. (a) what is its velocity at t = 1 s? (b) is it moving in the positive or negative direction of x just then? (c) what is its speed just then? (d) is the speed increasing or decreasing just then? (try answering the next two questions without further calculation.) (e) is there ever an instant when the velocity is zero? if so, give the time t; if not, answer "0". (f) is there a time after t = 3 s when the particle is moving in the negative direction of x? if so, give the time t; if not, answer "0".

Ais not a mixture. colloid compound suspension solution