A 47.4 kg student runs down the sidewalk and jumps w/ a horizontal speed of 4.2 m/s onto a stationary skateboard. The student and skateboard move down the sidewalk w/ a speed of 3.95 m/s. What is the mass of the skateboard?

Astudent is performing an experiment comparing sound and light waves. the student gathers the following data. what conclusion does the student most likely make based on this data? light waves always travel the same speed; however, the speed of sound is determined by the medium that it travels through. all sound waves always have the same energy, so the temperature of the medium does not affect wave speed. light needs to vibrate particles, so it travels fastest in tightly packed solids, while sound does not need a medium, so it travels fastest in a gas. tightly packed particles in solids slow down the light waves; however, sound waves make particles bounce into each other, so they travel faster in solids.

Explain what it means to view something from a frame of reference. provide an example that illustrates your explanation. (4 points)

An electron in an x-ray machine is accelerated through a potential difference of 1.00 × 104 v before it hits the target. what is the kinetic energy of the electron in electron volts?