Amass on a spring undergoes shm. when the mass passes through the equilibrium position, which statement about it is true? explain a) its acceleration is a maximum. b) its elastic potential energy is zero. c) its total mechanical energy is zero. d) its kinetic energy is a zero. e) its speed is zero.

Amass has an acceleration of 10- 2t. what is its velocity and displacement if it started at x- 4m and the initial velocity was 8m/s? at what time does it have 0 velocity? graph all graphs.

What is the length x of the side of the triangle below? (hint: use the cosine function)

Electric field of the earth. the earth has a net electric charge that causes a field at points near its surface equal to 150 n> c and directed in toward the center of the earth. (a) what magnitude and sign of charge would a 60-kg human have to acquire to overcome his or her weight by the force exerted by the earth’s electric field? (b) what would be the force of repulsion between two people each with the charge calculated in part (a) and separated by a distance of 100 m? is use of the earth’s electric field a feasible means of flight? why or why not?