The best frequency should be 70 Hz you simply find the difference between 280 Hz and 210 Hz
Explanation:
Simply, shake the boxes. The box that is difficult to shake will be the sand and the box that will be easier will be the feathers.
Answer and Explanation:
Hydrostatic equilibrium is the condition in which force is balance that is upward force and downward force the downward force is due to gravitational force and the upward force is due to the pressure. The Sun is said to be in hydrostatic equilibrium means the force acting on it is balance means upward force which is due to pressure is same as the force exerted by gravitation.