You drop a penny from the roof directly above the ground and the penny starts falling. After 3 seconds, the penny is 54 feet above the ground. After 5 seconds the penny is 30 feet above the ground. How fast is the penny falling? When will the penny hit the ground? At what height above the ground was the penny dropped?

Question

nincompoop · Answer

http://books.google.com/books?id=9ue4xAjkU2oC&pg=PA290&lpg=PA290&dq=s(t)%3D-16t%5E2%2B64t%2B80&source=bl&ots=-XZW8NHTke&sig=lQIoHJB2Ygb9zYBRSudgecg1NtQ&hl=en&sa=X&ei=vCGJUvzhPOmx2AWrtYHYCw&ved=0CEsQ6AEwBA#v=onepage&q=s(t)%3D-16t%5E2%2B64t%2B80&f=false

nincompoop · Answer

read about free-fall and if you donot understand, let me know

anonymous · Answer

I did not understand :(

anonymous · Answer

my teacher assigned  this problem without teaching the class

nincompoop · Answer

I see

nincompoop · Answer

are you in a pre-calculus or calculus class?

anonymous · Answer

pre-calculus

nincompoop · Answer

okay. so you get a feel of what functions are?

anonymous · Answer

yess

anonymous · Answer

@AyGee ya still need help?

nincompoop · Answer

ignoring friction, the penny and anything should fall at the same constant rate.