4. A weightlifter raises a mass mat a constant speed to a height h in time t. Which of the following expressions corresponds with the work done by the weightlifter?
a. mgh
b.-mgh
C. mgh/t
d. -mgh/

An electron and a proton have the same kinetic energy upon entering a region of constant magnetic field and their velocity vectors are perpendicular to the magnetic field. suppose the magnetic field is strong enough to allow the particles to circle in the field. note: you'll need to look up the masses for an electron and proton. 1) what is the ratio of the radii of their circular paths rp/re?

What type of nuclear decay causes the atomic number of an element to increase by 1?

The experiment was repeated many years later but the gases were mixed in a different type of container. a white solid was obtained which was xenon fluoride. predict whether you think 1) krypton and 2) radon will react with fluorine. explain reasons for your predictions