Answer:
Variance is 25
Explanation:
Recall that the standard deviation is defined as the square root of the variance. therefore, if you know the standard deviation
, square it and you get the variance:

Answer = 6.24x10^18 x ((2 x 3600) + (47 x 60) + 10)
a). When the piano reaches terminal speed, it is no longer accelerating,
so the net force on it must be <em>zero</em>.
b). If the net force on the piano is zero, the upward force of air resistance on it
must be exactly equal to the downward force of gravity ... <em>10,000 N</em>.