29. Two friends are pushing a crate in the same direction. One friend is pushing with a force of 250 N while the other friend is pushing with a force of 180 N. The surface they are pushing on
has a friction force of 20 N in the opposite direction. What is the net force acting on the crate?
PLEASE PLEASE HELP!

Where is the potential energy throughout the loading, cocking, and releasing of the trebuchet?

Atemperature inversion can cause a warm air mass to move over a colder air mass. this traps the colder air mass and prevents surface air from rising. this may result in which of these? a) smog b) acid rain c) freezing rain d) a thunderstorm

Consider a u-tube whose arms are open to the atmosphere. now equal volumes of water and light oil (ρ = 49.3 lbm/ft3) are poured from different arms. a person blows from the oil side of the u-tube until the contact surface of the two fluids moves to the bottom of the u-tube, and therefore, the liquid levels in the two arms are the same. if the fluid height in each arm is 30 in, determine the gage pressure exerted by the person on the oil by blowing.