A small 2.0 g mass is suspended from a massless thread. An unknown charge \"q\"
ID: 1878596 • Letter: A
Question
A small 2.0 g mass is suspended from a massless thread. An unknown charge "q" is placed on the mass. When a horizontal electric field having magnitude 2000 N/C pointing left to right is applied, the mass moves to the position shown and then comes to a stop, with the thread making a 40* angle with the vertical.
a) Is the charge q positive or negative? (DO NOT NEED HELP WITH THIS ONE)
b) How many forces are acting on the charged 2.0 g mass? What are they? (DO NOT NEED HELP WITH THIS ONE)
c) Calculate the magnitude of the charge "q" present on the mass. Give your answer in microcoulombs. Hint: Draw a Free Body Diagram for the charged mass. (DO NEED HELP WITH THIS ONE)
Explanation / Answer
depending upon your coemments, I am giving answer to part c:
Let the tension in thread = T
T cos 40 = mg
T sin 40 = qE
tan 40 = qE/ mg
0.839 = q ( 2000) / (2 x 10^-3 x 9.8)
q=8.22 micro C apprx