Answer:
The mass of Uranium present in a 1.2mg sample is 
Explanation:
The ration between Uranium mass and total sample mass is:
For a sample of mass 1.2 mg, the amount of uranium is:

Answer:
9 volts (assuming 0.60 is in Amperes)
Explanation:
Recall that Ohms law can be expressed as
V = IR, where
V = voltage,
I = current (given as 0.6. I'm going to assume that the units is Amperes because it is not given)
R = resistance (given as 15 ohm)
substituting the above values into the formula
V = IR
V = (0.6)(15)
V = 9 Volts
Answer:
70509.8039216 N/C
Explanation:
k = Coulomb constant = 
q = Charge = 2.00 µC
l = Length of filament = 5.1 m
r = Radius of cylinder = 10 cm

Electric field is given by

The electric field at the surface of the cylinder is 70509.8039216 N/C
Answer:
Potential Energy = 294J, Kinetic Engergy = 48.02J
Explanation:
We have these formulas:
Potential Energy = mass * gravitational force * height (m) = 1 * 9.8 * 30 = 294(J)
Kinetic Energy = 1/2 * mass * velocity^2 = 1/2 * 1 * 9.8^2 = 48.02 (J)
As the rock falling at an acceleration of 9.8m/s^2 which means for each second, the rock increases 9.8m/s. I think we are missing time to find the instantaneous velocity, the formula is (initial displacement - final displacement)/ (initial time - final time) which will directly give the final answer for you.