4.5 Joules. I think it'd be 4.41, but when you round it, it's 4.5.
Density is mass over volume:

In your case, mass is 48 grams and volume is 12cm^3
If you put that into the equation, you will get your density:
Explanation:
It is given that,
Inductance,
RMS value of voltage,
Frequency, f = 60 Hz
We need to find the energy stored at t = (1 /185) s. It is assumed that energy stored in the inductor is zero at t = 0. So,
The current flowing through the inductor is given by :

I = 0.091 A
Energy stored in the inductor is, 

U = 0.000165 Joules
Hence, this is the required solution.
Answer:

Explanation:
From the question we are told that
Nucleus diameter 
a 12C nucleus
Required kinetic energy 
Generally initial speed of proton must be determined,applying the law of conservation of energy we have

where
=initial kinetic energy
=final kinetic energy
=initial electric potential
=final electric potential
mathematically

where
=distance b/w charges
=nucleus charge 
=constant
=proton charge
Generally kinetic energy is know as

Therefore
Generally equation for radius is 
Mathematically solving for radius of nucleus


Generally we can easily solving mathematically substitute into v_1









Therefore the proton must be fired out with a speed of 
Answer:
The component of F along AB is equal to Fcos45
F = 520N
Component along AB = 520cos45
= 367.7N
This is done by rotating the diamonds such that AB is now taken as the x-axis. Then the force F is resolved along AB.
Explanation: