The stretch of the spring is

The constant of the spring is k=15 N/m, so we can find the force produced by the weight by using Hook's law:
Answer:
6. A
7. C
8. B
9. The average speed is the distance (a scalar quantity) per time ratio. Speed is ignorant of direction. The average velocity is the displacement or position change (a vector quantity) per time ratio.
Answer: 1.8 g
Explanation:
We start first, by calculating the amount of Helium
n = m/M
m = mass of Helium
M = molar mass if Helium
n = 2/4 = 0.5 moles
proceeding further, we use ideal gas law. PV = nRT
Then we have
P1V1/n1T1 = P2V2/n2T2
So that,
n2 = n1T1P2V2/P1V1T2
From the question, we know that, P1 = P2, and T1 = T2. So that,
n2 = n1v2/v1
n2 = (0.5 * 3.9) / 2
n2 = 1.95/2
n2 = 0.975 moles. With this, we can determine the mass, m2 of Helium
n = m/M
m = n * M
m = 0.975 * 3.9
m = 3.8
The difference between both masses are 3.8 - 2 = 1.8 g
Thus, 1.8 g of Helium was added to the cylinder
It is a type capacitor is in which two metal plates arranged in such a way so that they are connected in parallel . The potential energy is stored in the capacitor will be 2.7×10⁻⁵.
<h3>What is parallel plate capacitor ?</h3>
It is an type capacitor is an in which two metal plates arranged in such a way so that they are connected in parallel and have some distance between them.
A dielectric medium is a must in between these plates. helps to stop the flow of electric current through it due to its non-conductive nature .
The given data in the problem is;
Q is the charge= 1.5 µC
V is the change in voltage across the plates is = 36 V.
U is the potential energy=?
The formula for the potential energy is given by;

Hence the potential energy is stored in the capacitor will be 2.7×10⁻⁵.
To learn more about the parallel plate capacitor refer to the link;
brainly.com/question/12883102
The continental crust
Hope it helps!!