Welcome to Westonci.ca, the place where your questions find answers from a community of knowledgeable experts. Get precise and detailed answers to your questions from a knowledgeable community of experts on our Q&A platform. Join our platform to connect with experts ready to provide precise answers to your questions in different areas.

A stone is thrown vertically downwards and the formula d = 5t^2 + 25t gives the distance, d metres, that it falls in t seconds. How long does it take to fall 1500 metres

Sagot :

Answer:

use the formula we know the distance is 1500 metres

put that in the formula

1500 = 5t^2 + 25t

Now we can factor out 5 as all the coefficients are multiples of 5

so

we get

300 = t^2 +5 t

now we solve for t using the quadratic factorization

t^2 +5t -300 = 0

which gives

(t - 15) =0

(t + 20 )= 0

so time cannot be negative hence

15 seconds is the answer