Answer: y = 40 + 21t
Explanation:
Apply the equation of distance covered.
d = vt + C
Where d is the distance covered
v = velocity , t = time
C = constant = initial distance covered
For the case above....
d = y
y(t) = vt + C
But y(0) =40 = C
C = 40ft
velocity v = 21 ft/s
Therefore, the equation of the altitude is given by;
y(t) = 21t +40
y = 40 + 21t