Answer:
4 hertz
Explanation:
The defination of freqyency = the total no of cycle made by a wave in one second .
so,
cycle or vibrations=60
tame taken = 15
now,
frequency = no. of cycle / time taken
= 60/15
=4 hertz
hence, the its frequency = 4hertz
The answer is C. Electrical;mechanical
Answer:
The lever arm could decrease or increase depending of the initial angle.
Explanation:
The lever arm d is calculated by:
d = rsin(θ)
where r is the radius and θ the angle between the force and the radius.
So, the increse or decrees of d depends of the sin of the angle θ, if the initial angle is greather than 90° and the angle decrease to an angle closer to 90°, the lever arm will increase but if the initial angle is 90° or lower and the angle decrease, the lever arm will decrease.
Decreases, stays the same, increases.
The volume decreases because as air is cooled, the individual molecules collectively possess less kinetic energy and the distances between them decrease, thus leading to a decrease in the volume they occupy at a certain pressure (please note that my answer only holds under constant pressure; air, as a gas, doesn't actually have a definite volume).
The mass stays the same because physical processes do not create or destroy matter. The law of conservation of mass is obeyed. You're only cooling the air, not adding more air molecules.
The density decreases because as the volume decreases and mass stays the same, you have the same mass occupying a smaller volume. Density is mass divided by volume, so as mass is held constant and volume decreases, density increases.
