1) Which of the equations below is dimension-(adsbygoogle = window.adsbygoogle || []).push({});

ally correct?

a. y = (2 m) cos(k x), k = 2 m^{-1}

b. v = v_{0}+ a x

my work for:

a) cos(kx) = 2ym^{-1}

So this would lead to k = (1/x)cos^{-1}(2ym^{-1})

But i dont know whether the COSINE operation on RHS changes m^{-1}to any other unit or not. So, please help me with that.

b) in this case i thought that the presence of two unknown quantities with unknown units on the RHS would mean that the dimension of "v" is correct or not. So i would say it cannot be determined

2) The volume of an object is given as a func-

tion of time by V = A+(B/t)+Ct^{4}. Determine

the dimension of the constant C.

1. L^{2}/T^{4}

2. L^{4}/T^{3}

3. L^{3}/T^{4}

4. L/T

5. L/T^{4}

My work:

V = A+(B/t)+Ct^{4}

so, V=A+(B+Ct^{5}/t)

or, C= {[(V-A)t]-B}/t^{5}

Which i thought would give the dimension for C as L/T^{4}. But i am not sure at all so please help.

**Physics Forums | Science Articles, Homework Help, Discussion**

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Question about Dimensions (very basic)

**Physics Forums | Science Articles, Homework Help, Discussion**