Electric force from electomagnetic force and force of gravity from gravitational force
Electrical energy.................
Answer:
Length is the unit of metre
Answer: 
Explanation:
We are told both planets describe a circular orbit around the star S. So, let's approach this problem begining with the angular velocity 
of the planet P1 with a period 
:
(1)
Where:
is the velocity of planet P1
is the radius of the orbit of planet P1
Finding :
(2)
(3)
(4)
On the other hand, we know the gravitational force 
between the star S with mass 
and the planet P1 with mass 
is:
(5)
Where 
is the Gravitational Constant and its value is 
In addition, the centripetal force 
exerted on the planet is:
(6)
Assuming this system is in equilibrium:
(7)
Substituting (5) and (6) in (7):
(8)
Finding :
(9)
(10)
Finally:
(11) This is the mass of the star S
Answer:
The density of the mixture is 0.55kg/m^3
Explanation:
P = 1bar = 100kN/m^2, T = 0°C = 273K, n = 0.4+0.6 = 1mole
PV = nRT
V = nRT/P = 1×8.314×273/100 = 22.70m^3
Mass of N2 = 0.4×28 = 11.2kg
Mass of H2 = 0.6×2 = 1.2kg
Mass of mixture = 11.2 + 1.2 = 12.4kg
Density of mixture = mass/volume = 12.4/22.7 = 0.55kg/m^3
