Answer:
0.33 s
Explanation:
For this case, as the object is hung on the end of an unstretched spring, we can consider this system as a simple pendulum.
For this system, we can determine the period of the motion using the following formula:
T = 2π√(L/g)
Where: T = period (in sec), L = lenght of the spring, g = acceleration of garvity = 9.8 m/s²
By the exact time the object is 2.75 cm before coming to rest, that will be the lenght of the spring we can consider (2.75 cm = 0.0275 m)
Finally:
T = 2π√(0.00275/9.8)
T = 0.33 sec
0.33 . Equation is Force of friction equals normal force times coefficient of friction, so 6=18u. Divide 6 by 18
Answer:
E = 77532.42N/C
Explanation:
In order to find the magnitude of the electric field for a point that is in between the inner radius and outer radius, you take into account the Gauss' law for the electric flux trough a spherical surface with radius r:
(1)
Q: net charge of the hollow sphere = 1.9*10-6C
ε0: dielectric permittivity of vacuum = 8.85*10^-12 C^2/Nm^2
Furthermore, you have that the net charge contained in a sphere of radius r is:
(2)
with the charge density is:
(3)
r2: outer radius = 0.31m
r1: inner radius = 0.105m
The electric field trough the Gaussian surface is parallel to the normal to the surface, the, you have in the integral of the equation (1):
(4)
where you have used the expression for a surface of a sphere.
Next, you replace the expressions of equations (2), (3) and (4) in the equation (1) and solve for E:

you replace the values of all parameters, and with r = 0.17m

The magnitude of the electric field at a distance r=0.17m to the center of the hollow sphere is 77532.42N/C
I think it c or d it one I those
The rule is always the same. Your final answer must have the same number of significant figures as the least accurate value in the calculation (one with the least number of significant figures) I hope this makes sense