You are Here: Home >< Maths

# Ball thrown off a building time question

1. Been given this question, and I'm sure it's to be solved with a quadratic equation but it's not really working out for me so far.

A ball's been thrown off a building and it's going at 60 km per hour, the building is 100 meters tall and the distance before it reaches the ground is;

d = ½gt^2 + vt

g = gravity and it's 10 ms^-2
t = time in seconds
v = initial velocity

I've to find the time for the ball when it's dropped ¼ the height of the building.

so I got;

5t^2 + 60t - 25 = 0

Am I on the right track?
2. (Original post by Brainfrozen)
Been given this question, and I'm sure it's to be solved with a quadratic equation but it's not really working out for me so far.

A ball's been thrown off a building and it's going at 60 km per hour, the building is 100 meters tall and the distance before it reaches the ground is;

d = ½gt^2 + vt

g = gravity and it's 10 ms^-2
t = time in seconds
v = initial velocity

I've to find the time for the ball when it's dropped ¼ the height of the building.

so I got;

5t^2 + 60t - 25 = 0

Am I on the right track?
You should probably covert from km/h to m/s before plugging that speed in since right now the equation doesn't make sense, otherwise you're on the right track.
3. (Original post by RDKGames)
You should probably covert from km/h to m/s before plugging that speed in since right now the equation doesn't make sense, otherwise you're on the right track.
It's sorted, thanks for your help!

Write a reply… Reply
Submit reply

## Register

Thanks for posting! You just need to create an account in order to submit the post
1. this can't be left blank
that username has been taken, please choose another Forgotten your password?
2. this can't be left blank
this email is already registered. Forgotten your password?
3. this can't be left blank

6 characters or longer with both numbers and letters is safer

4. this can't be left empty
your full birthday is required
1. Oops, you need to agree to our Ts&Cs to register
2. Slide to join now Processing…

Updated: October 17, 2016
TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Today on TSR

### Struggling with revision?

Use our free tools and resources

Poll
Useful resources

## Make your revision easier

### Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

### How to use LaTex

Writing equations the easy way

### Study habits of A* students

Top tips from students who have already aced their exams

Can you help? Study help unanswered threads

## Groups associated with this forum:

View associated groups
Study resources

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.