You are Here: Home

# Help with M1 question

Announcements Posted on
TSR's new app is coming! Sign up here to try it first >> 17-10-2016
1. At time t = 0, two balls A and B are projected vertically upwards. The ball A is projected vertically upwards with speed 2m/s from a point 50m above the horizontal ground. The ball B is projected vertically upwards from the ground with speed 20m/s. At time t = T seconds, the two balls are at the same vertical height, h metres, above the ground. The balls are modelled as particles moving freely under gravity.

I've got to the point where I have two equations:

Ball A -
h-50=2T+1/2(-9.8)t2

Ball B -
h=20T+1/2(-9.8)t2

What do I have to do now to solve h and T?
2. Any help will be appreciated!
3. (Original post by ℓove)
At time t = 0, two balls A and B are projected vertically upwards. The ball A is projected vertically upwards with speed 2m/s from a point 50m above the horizontal ground. The ball B is projected vertically upwards from the ground with speed 20m/s. At time t = T seconds, the two balls are at the same vertical height, h metres, above the ground. The balls are modelled as particles moving freely under gravity.

I've got to the point where I have two equations:

Ball A -
h-50=2T+1/2(-9.8)t2

Ball B -
h=20T+1/2(-9.8)t2

What do I have to do now to solve h and T?
This is simply simultaneous equations, and so, assuming your equations are correct, we can subtract Ball A from Ball B, giving:

h-(h-50)=20T+1/2(-9.8)T2 -(2T+ 1/2(-9.8)T2)

50=18T

T=50/18

Then we can solve

h=20*T+1/2(-9.8)T2 plugging in our T value

4. (Original post by mathematigeek)
This is simply simultaneous equations, and so, assuming your equations are correct, we can subtract Ball A from Ball B, giving:

h-(h-50)=20T+1/2(-9.8)T2 -(2T+ 1/2(-9.8)T2)

50=18T

T=50/18

Then we can solve

h=20*T+1/2(-9.8)T2 plugging in our T value

Thanks!!!!!

## Register

Thanks for posting! You just need to create an account in order to submit the post
1. this can't be left blank
2. this can't be left blank
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
1. Oops, you need to agree to our Ts&Cs to register

Updated: September 25, 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

### How does exam reform affect you?

From GCSE to A level, it's all changing

### Who would you like to thank?

Poll
Useful resources
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.