Scientific define mass
In physical science, mass is a measure of the number of atoms in an object combined with the density of those atoms. The mass of an object determines how that object responds to forces such as gravity and friction. The typical unit of measure for mass is kilograms.
Answer:

Step-by-step explanation:
Given


Required:
Determine the time taken to return to the ground
From the equation given; height (h) is a function of time (t)
When the rocket returns to the ground level, h(t) = 0
Substitute 0 for h(t) in the given equation

becomes

Solve for t in the above equation

Factorize the above expression

Split the expression to 2

Solving the first expression

Divide both sides by -4



Solving the second expression

Add 30 to both sides


Divide both sides by 4



Hence, the values of t are:
and 
shows the time before the launching the rocket
while
shows the time after the rocket returns to the floor
44, if you’re asking about the next one
Answer:
Step-by-step explanation:
Answer:
7.5 hours
Step-by-step explanation:
We can model an equation for this problem.
We can write:

Where
F is the final temperature (15 degrees we need)
m is the rate of temperature change (2 degrees per hour)
and
t is the time, in hours, it will take (we need to find this)
It is given,
F = 15
m = 2
So, t would be:
F = mt
15 = 2t
t = 15/2 = 7.5
So it will take 7.5 hours