Answer: 7.436 s
Explanation:
This situation is related to vertical motion, specifically free fall and can be modelled by the following equation:
Where:
is the final height of the object (when it makes splash)
is the initial height of the object
is the initial velocity of the object (it was dropped)
is the acceleration due gravity (directed downwards)
is the time since the objecct is dropped until it makes splash
Clearing
:
Finally:
<span>This statement simply implies that the 50 million tons of coal will produce the same energy output in one year as the 0.6 million barrels per day of oil. Assuming coal is more plentiful than oil, this is significant as 50 million tons is much smaller than 219 million barrels of oil.</span>
The power developed is 500 W ( to the nearest Watt)
Power(P) is the rate at which work is done. Work done (W) is the product of the force applied on the object and the displacement (s) made by the point of application of the force.


Therefore,

Substitute the given values of force , displacement and time


Thus the Power can be rounded off to the nearest value of 500 W
The correct answer is<span> B.The speed of sound in air is directly proportional to the temperature of the air.
When the temperature increases so does the speed of sound. Sound is faster by </span>0.60 m/s for every higher degree in air temperature because the air density is reduced and the sound can travel faster.