Need some help with acceleration.

1. The problem statement, all variables and given/known data

1.) A brick has a mass of 2kg, how much (In Newtons) does it weigh?
If you drop it, what is its acceleration? (ignoring air resistance)?

2. Relevant equations
Im not sure


3. The attempt at a solution
I found that 1kg = 10N, so 2kg =20 newtons, and I think that if you dropped it, since gravity is 10N (rounded up, which is what our teacher told us to do) then its acceleration would be 10N, but im not sure that's right.

 

My teacher thinks it's not that important to teach the formula's, but I do remember that F=ma , but i don't see how that applies here? Since I know that dropping the brick it would accelerate 10m/s every second.

 

sorry for putting it in N, im still getting used to putting the right things beside the numbers. Would it be 10m/s?

 

I've actually got one more question if you guys don't mind helping me out again :D

1.) What is the impact speed when a car moving 100km/h Bumps into the rear of another car traveling in the same direction at 98km/h

Now here I would just think that you would take 100 + 98 and then divide them by 2, giving you an answer of 99km/h?

 

2? since your already going 98kg/h, the other car is going 100kg/h so when it bumps you, the impact speed is two more than your already going?

 

Awesome! Thanks for the help!