You are Here: Home >< Maths

# M3 Gravity watch

1. Could someone explain the signs of the first line of the solution, wouldn't the acceleration for Q6 be in the same direction as gravity so the signs be the same? Or are the signs always different since they have to add up to zero?
2. Do you mean the bit about "the acceleration is in the direction of decreasing x"?

If so, I usually think of it like this - acceleration is towards the earth, but x is measured from the earth, so they're in different directions.

I may have misunderstood your question; sorry if so.
3. (Original post by phys981)
Do you mean the bit about "the acceleration is in the direction of decreasing x"?

If so, I usually think of it like this - acceleration is towards the earth, but x is measured from the earth, so they're in different directions.

I may have misunderstood your question; sorry if so.
Thanks that makes sense, I've realised that theyre both negative since x increases in the opposite direction to the acceleration.

### Related university courses

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:
Updated: February 18, 2018
The home of Results and Clearing

### 2,754

people online now

### 1,567,000

students helped last year
Today on TSR

### University open days

1. SAE Institute
Animation, Audio, Film, Games, Music, Business, Web Further education
Thu, 16 Aug '18
2. Bournemouth University
Fri, 17 Aug '18
3. University of Bolton
Fri, 17 Aug '18
Poll
Useful resources

### 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