Answer:
3.77min
Step-by-step explanation:
we are given the relationship:
d = Vt + 4.9t²,
where
d = distance in meters = given as 160m
V = launching (aka initial) speed = 24m/min
t = time in min (we are asked to find this)
if we subsititute the above values into the equation:
d = Vt + 4.9t²
160 = 24t + 4.9t²
4.9t² + 24t - 160 = 0 (we simply solve for t)
Using the quadratic formula:
t = { -24 ± √[24² - (4)(4.9)(-160] } / [(2)(4.9)] }
t = 3.77 min or -8.67 min
because time cannot be negative in this case, we pick the positive number.
t = 3.77min