Which of these would best define sound intensity? a) how fast the wave is traveling b) the frequency of the sound wave c) the power of the sound wave per unit area d) the mass of the wave divided by its volume

Sound intensity =  The power of the sound wave per unit area

Explanation:

Sound intensity is defined as the the power of the sound wave per unit area. Mathematically, it is given by :

P is the power

A is the area

It is also defined as the amount of energy flowing per unit time per unit area of cross section.

The SI unit of power is watts and the SI unit of area is m². So, the SI unit of sound intensity is W/m². Hence, the correct option is (C).

the minimum constant speed at which she can catch the train is 2.7 m/s

given:

acceleration = 0.6

time = 4.5 s

to find:

velocity = ?

formula used:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

solution:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

v = 0 + (0.6 × 4.5)

v = 2.7 m/s

the minimum constant speed at which she can catch the train is 2.7 m/s