# Help with simple dimensional analysis question

Which one of the quantities below has dimensions equal to ML/T2

a) mv
b) mv2
c) mv2/r
d) mrv
e) mrv2/r2

I tried splitting it up in M*(L/T)*1/T
which would lead me to mv*T-1 and then I get stuck

Redbelly98
Staff Emeritus
Homework Helper
Welcome to Physics Forums Since it's multiple choice, how about examining each answer and seeing if it matches ML/T2

For example:

a) mv = M L/T (is not ML/T2)
etc.

Welcome to Physics Forums Since it's multiple choice, how about examining each answer and seeing if it matches ML/T2

For example:

a) mv = M L/T (is not ML/T2)
etc.

I'm working on it, but what is the r in the answers? Also, why does the m become a capital M?

Redbelly98
Staff Emeritus
Homework Helper
For dimensional analysis problems, it's customary to use capital letter M, L and T for Mass, Length, and Time.

r is a distance or length.

Ok, I think I figured it out...

I took mv2/r

(M(L/T)(L/T))/r

I assumed r = L since both are length measures so...

(M(LL/TT))/L

(M(LL/TTL)

M(L/TT)

M(L/T2)

I don't know if I should be equating r to L though...

Redbelly98
Staff Emeritus