Velocity of sound increases on a cloudy day. why?

Because there's a decrease in density.

Explanation:

For fluids, the speed of sound (Vs) is given by the relationship :

, where:

Ks = coefficient of stiffness, the isentropic bulk modulus (or the modulus of bulk elasticity for gases).

d = density of the fluid.

As we can see, speed of sound is inversely proportional to density. If density decreases, speed of sound increases.

In a cloudy day, humidity is very high (in fact, when it rains, relative humidity is 100% (maximum) which is why the clouds can't hold any more water). Density is inversely proportional to humidity. So, in a cloudy (or highly humid) day, density decreases, causing an increment in the velocity of sound.

note: the given question is incomplete.

complete question is given below.

which is an example of kinetic energy?

a. the energy stored in ethanol  

b. a hockey puck sliding across the ice  

c. a compressed spring  

d. a ball sitting at the top of a ramp

solution: the kinetic energy is the energy posses by the virtue of the motion of the object.

in the given options, a, c and d are the example of potential energy because it is the energy posses by the virtue of the rest of the object. but option b has the kinetic energy as the object is in motion.

hence, a hockey puck sliding across the ice   is the apex example of kinetic energy.

so, the option (b) a hockey puck sliding across the ice   is the correct option.