Two identical steel balls, each of diameter 24.8 mm and moving in opposite directions at 4 m/s, run into each other head-on and bounce apart. prior to the collision, one of the balls is squeezed in a vise precise measurements are made of the resulting amount of compression. the results show that hooke's law is a fair model for the ball's elastic behavior. for one datum, a force of 25 kn exerted by each jaw of the vise results in a 0.5-mm reduction in the ball's diameter. the diameter returns to its original value when the force is removed. modeling the ball as a spring, find its spring constant.

The x-coordinate of a particle in curvilinear motion is given by x = 3.1t3 - 4.9t where x is in feet and t is in seconds. the y-component of acceleration in feet per second squared is given by ay = 2.3t. if the particle has y-components y = 0 and vy = 5.0 ft/sec when t = 0, find the magnitudes of the velocity v and acceleration a when t = 1.8 sec. sketch the path for the first 1.8 seconds of motion, and show the velocity and acceleration vectors for t = 1.8 sec. answers: v = ft/sec a = ft/sec2

What is a neurotransmitter involved in mood reward, addiction, and motor behaviors?

Cells in the nervous system have a potential difference of 70 mv across the cell membrane separating the interior of the cell from the extracellular fluid. this potential difference is maintained by ion pumps that move charged ions across the membrane. is this an emf? select the correct answer and explanation. 1)no. the ion pumps cannot separate charges; thus, they cannot create a potential difference. 2)yes. the ion pumps cannot separate charges, but they still can create a potential difference. 3)yes. the ion pumps can actively separate charge; thus, they can create a potential difference. 4)no. the ion pumps can separate charges, but they cannot create a potential difference.