Question

Please help..
Find the height of an object 5 seconds after it has been projected upward at a rate of 120 feet per second.

Answer 1

Assuming we're on earth, we know gravity is a constant -32 ft/s^2
a(t)=a
v(t)=v(o)+at
x(t)=x(o)+v(o)t+(1/2)at^2
x(o)=0, we know v(o), and we know a=-32 ft/s^2
now just plug in t=5s and solve for x

Answer 2

The equation my book give me is h=-16t^2+v(o)t...
Is this the same as what you wrote or is it different?
Aslo with that equation h=-16*5^2+120(0)5
How do I work out the 120(0)5?

Answer 3

@dannym

Answer 4

you want to find when h , when t = 5

Answer 5

the V(o) there doesnt mean velocity * zero it means Vo initial velocity

Answer 6

I've got that..

Answer 7

Ok so the V(o)t would be the 120*5?

Answer 8

yes

Answer 9

Ok thank you!

Answer 10

oh and is that equation given to you, are are you expected to find it yourself

Answer 11

or are*

Answer 12

It was given to me in my book.

Answer 13

lol hey guess what 1/2 * 32 is????

Answer 14

ok never mind

Answer 15

dannym was trying to show you from integration how to derive any equation for these kinda questions when you dont take into account the frictional air forces

Answer 16

Thank you both! Much appreciated!

Answer 17

yea sure thing..