Free Fall Equations on hot air balloon

[matace50]

Homework Statement

A hot-air balloon is descending at a rate of 2.0 m/s when a passenger drops a camera. If a camera is 45m above the ground when it is dropped, (a) how long does it take for the camera to reach the ground(b) what is the velocity just before it lands? Let upward be the positive direction for this problem.

Homework Equations

I have to use either 2a x change in displacement= final velocity^2 - initial velocity^2 or
change in displacement= 1/2a x t^2 + initial velocity x change in time

a = acceleration t= time ^2= squared x= multiply

The Attempt at a Solution

I think i somehow have to rearrange the equation to isolate t but i have no idea how. Can anyone help

 

[learningphysics]

For the first part, use the equation:

d = v1*t + (1/2)at^2

careful about signs... decide first if you want upward to be positive, or downward to be positive...

 

[matace50]

I see, but the problem doesn't give me time. I plugged everything in, but i still can't seem to get time.

(just started physics 2 weeks ago so I am kind of confused)

 

[learningphysics]

I see, but the problem doesn't give me time. I plugged everything in, but i still can't seem to get time.

(just started physics 2 weeks ago so I am kind of confused)

You have to use the quadratic formula to solve for time.

 

[matace50]

Ok now i understand. Thanks