Question

Britney throws an object into the air with an initial vertical velocity of 27 ft/s from a platform that is 10 ft above the ground. About how long will it take the object to hit the ground?

A. 1 s
b. 2 s
c. 3 s
d. 4 s

Answer 1

@mathmate

Answer 2

@yayah2001
Are you on energy conservation or kinematics?
Both will solve the problem, but it's better to work with the one you're studying.

Answer 3

conservation

Answer 4

this is math!

Answer 5

So you're on calculus?

Answer 6

algebra

Answer 7

Do you have the kinematics equation given to you?
like:
x(t)=vt+(1/2)at^2

Answer 8

I have h(t)=-4.9t^2 + VoT +Ho

Answer 9

x(t)=-10
v=+27
a=-32.2
Solve for t.

Answer 10

That is assuming the ball was thrown vertically \(upwards\)

Answer 11

and reject the negative root from the quadratic equation.

Answer 12

That's the same equation, but the number -4.9 should read -16 or -16.1, because you are working with feet, not metres.

Answer 13

okay, I understand now.

Answer 14

or not

Answer 15

Take your time and post the answer to check if you wish.
Please give me the answer to 2 places of decimals, even though you have to round it to an integer later on.
Remember to reject the negative root.

Answer 16

I have to change it to a different question because I got a 70%

Answer 17

ok, anyway, the principle is the same.

Answer 18

I really just need the answer. I've tried really hard to get the equation right (I spent 10 minutes on just the one question), so could you possibly go easy on me?

Answer 19

with the new question, of course.