# Need Physics help !

1. Aug 31, 2011

### deluxenathan

Need Physics help urgent!

A man pushes an empty 20kg cart as hard as he can and the cart accelerates at 10m/s. The cart is then filled so that the weight is 100kg. How much acceleration can the man achieve pushing the full cart? (Show all your working)

Hi thats the question i need to do ive done most of the working out i just dont understand the algebra in it and where it goes so if someone could fill and algebra out for me that would be great

ive added a attachment with the working out ive done so far.

#### Attached Files:

• ###### bfd.png
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2. Aug 31, 2011

### HallsofIvy

Staff Emeritus
Re: Need Physics help urgent!

You have two different accelerations so call them a and a'. You have F= ma and F= (5m)a'. F and m are the same.

3. Sep 1, 2011

### Lobezno

Re: Need Physics help urgent!

He has acceleration as different, in the attachment at least.

It's fine what you're doing so far, but in my head, it works better by finding the force using Newton's Second:

F=ma -> F=20*10

Then you can plug it into any other equation as the force value, and you can get acceleration for a known mass (or mass for a known acceleration).