The same force will give a mass of 3 M an acceleration of what?

Question

A force of F newtons will give an object with a mass of M an acceleration of A. The same force will give a mass of 3 M an acceleration of:

 

Multiple choice:

a) 1/3 A

b) 3 A

c) A

d) 1/9 A

 

I know the answer is a)1/3 A.

But, how do I show that.. please help me show work please

Answer 1

F = ma

 

if m = 3m

 

then F = (3m)*a

 

if we rearrange F = ma to be a = F/m  then we get

 

a = F/3m   but we just said that a = F/m so in the equation we can replace F/m with a

 

so a = (1/3)a  .

 

Hopefully that helps.