Please help with this maths question?

Question

In the following question find the SI unit of A.

A = square root of hc / G

and where the SI unit of h is Js

The SI unit of c is Ms-1

The SI unit of G is J m Kg -2

Answer 1

I'm assuming that "J m Kg -2" means J m kg^-2.

Then
A = sqrt(( J*s*(m/s))/(J*m/(kg*kg))
= sqrt(J*s*m*kg*kg)/(s*J*m))
= sqrt(kg*kg)
= kg

So, it's a unit of mass.

Answer 2

Hey.

You have to know the formulas, so that you can find the units

ie: F = m a

a = dv/dt

v = dx / dt

So, the units from v are m/s in the SI

The units from a are the units from v divided by the units from t. So, they are m/s^2

The units from F are kg by the units from a, kg m/s^2, this is 1 N

Etc.

Remember that Work is difference of Energy. And Work is the scalar product F*x, so the units will be kg m^2/s^2, this is a J

You only must learn how to work with the power of the units. ie: when you divide ms^'1 by s, you are multiplying ms^-1 by s^-1. Remember that the exponents are added

Later

Ana

Answer 3

A=sq rt of hc/G
=sq.rt of Js*Ms^-1/Jmkg^-2
from the data supplied by you this is what it is

Answer 4

OK
hc/G = ((J/s)*M/s)/(J*M/Kg²) = (J*M/s²)/(J*M/Kg²) =
(J*M/s²)*(Kg²/J*M) = Kg²/s² and taking the square root
√Kg²/s² = Kg/s

Doug