Which of the following forces can change velocity? acceleration forces equal and opposite horizontal forces equal and opposite vertical forces unequal, opposite forces

This is how zirconium appears in the periodic table. rounded to the nearest whole number, how many electrons are in an atom of zirconium?

Arunner is training for an upcoming marathon by running around a 100-m-diameter circular track at constant speed. let a coordinate system have its origin at the center of the circle with the x-axis pointing east and the y-axis north. the runner starts at (x, y) = (50 m, 0 m) and runs 2.5 times around the track in a clockwise direction.

What is the coefficient of kinetic friction μk between the block and the tabletop?