If an element has 20 protons and 20 neutrons in the nucleus of its atoms , what is the mass number of the atom?

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

Explain what happens at the saturation point when adding salt to water at room temperature.

What is the force that opposes motion and works against the downward pull? a) friction b) gravity c) weight d) acceleration