An astronaut on the moon throws a baseball upward. The astronaut is 6 ft 6 in tall, and the initial velocity of the ball is 40 ft per sec. The heights of the ball in feet is given by the equation S = -2.7t^2+40t+6.5, where t is the number of seconds after the ball was thrown.

After how many seconds is the ball 18 ft above the moon's surface?

t = 0.293 s and 14.52 s

Step-by-step explanation:

The heights of the ball in feet is given by the equation as follows :

Where t is the number of seconds after the ball was thrown.

We need to find is the ball 18 ft above the moon's surface.

Put S = 18 ft

It is a quadratic equation. Its solution is given by :

So, the ball is at first 0.293 s and then 14.52 s above the Moon's surface.

answer: what do you mean

not only in mathematics, scientific proof also are required in the other field of science. also maths proofs are of particular structure, containing steps and logics. so proving is like doing science, it is science. that's why it is important to prove. 

an inaccurate proof leads to errors, or stating results that are not accurate.  which wil mess the probelm up you dont want this