A stationary body is acted upon by a number of forces. State two conditions which must apply for the body to remain at rest can someone help pls

What’s #16 asking and how do i solve it?

State the following: boyle's law and charle's law

During a medieval siege of a castle, the attacking army uses a trebuchet to hurl heavy stones at the castle walls. if the trebuchet launches the stones with a velocity of at an angle of 50.0°, (a) how long does it take the stone to hit the ground? (b) what is the maximum distance that the trebuchet can be from the castle wall to be in range? (c) how high will the stones go? show all your work.