Answer:
(a) 8 V, (b) 144000 V, (c) 2 x 10^(-8) C
Explanation:
(a) charge, q = 5 μC , Work, W = 40 x 10-^(-6) J
The electric potential is given by
W = q V

(b)
charge, q = 8 x 10^(-6) C, distance, r = 50 cm = 0.5 m
Let the potential is V.

(c)
Work, W = 8 x 10^(-5) J, Potential difference, V = 4000 V
Let the charge is q.
W= q V

Answer:
Around 2.8212 sec
Explanation:
Given the eqn x=1/2at^2+vot
your vo=0
39=1/2(-9.8)t^2
=7.95=t^2
=2.82sec
E=hf C=wavelength*F
E=hC/wavelength
E=(6.626*10^-34)*(3.00*10^8)/670*10^-9
E=(6.626*10^-34)*(3.00*10^8)/450*10^-9
There are some missing data in the text of the problem. I've found them online:
a) coefficient of friction dry steel piston - steel cilinder: 0.3
b) coefficient of friction with oil in between the surfaces: 0.03
Solution:
a) The force F applied by the person (300 N) must be at least equal to the frictional force, given by:

where

is the coefficient of friction, while N is the normal force. So we have:

since we know that F=300 N and

, we can find N, the magnitude of the normal force:

b) The problem is identical to that of the first part; however, this time the coefficienct of friction is

due to the presence of the oil. Therefore, we have:
You can only determine the speed since the only info we know is how much you ran in how long of a time.