Which type of mechanical wave needs a source of energy to produce it?
a. a transverse wave
b. a longitudinal wave
c. a surface wave
d. all of the above

The chemical effect of the endocrine system is longer lasting than the chemical effect of the nervous system. select the best answer from the choices provided t f

What properties of a moving object are used in determining the object's energy of motion

Atank has a shape of a cone with a radius at the top of 2 m and a height of 5 m. the tank also has a 1 m spout at the top of the tank. the tank is filled with water up to a height of 2 m. find the work needed to pump all the water out the top of the spout. (use 9.8 m/s2 for g and the fact that the density of water is 1000 kg/m3.)