Achild drops a ball from a window. the ball strikes the ground in 3.0seconds. what is the velocity if the ball the instant before it hits the ground

Abeam has a square cross-section, a x a, where a is the linear dimension, and is subject to a pure bending moment, m. m is known with an uncertainty of 10% and a is known with an uncertainty of 5%. the strength of the material is known to an uncertainty of 12%. find the minimum design factor such that the beam is guaranteed not to fail.

If a tank filled with water contains a block and the height of the water above point a within the block is 0.8 meter, what is the pressure at point a?

(**i would really appreciate if this was answered soon** ) which pair of quantities includes one quantity that increases as the other decreases during simple harmonic motion?