Work can be obtained from the following expression
W = F*d
Where F is the force (In this case the force it takes to lift Sarah, which is mass*gravity)
And d is the distance traveled.
W = 60kg*9.8m/s^2 * 4m = 2352 Joules
Answer:
The charge in each ball will be 3 * 10^-12 C
Explanation:
(Assuming the correct charge of the second ball is 8 * 10^-12)
When the balls are brought in contact, all the charges are split evenly among then.
So first we need to find the total charge combined:
(-3 * 10^-12) + (8 * 10^-12) + (4 * 10^-12) = 9 * 10^-12 C
Then, when the balls are separated, each ball will have one third of the total charge, so in the end they will have the same charge:
(9 * 10^-12) / 3 = 3 * 10^-12 C
So the charge in each ball will be 3 * 10^-12 C
can't read it, need larger picture
This question is just a fancy case of angle of incidence = angle of reflection. Instead of focusing on the blue lines, focus on the red arrow. By following these steps you will be able to draw your diagram:
1. Extend the red arrow until it touches the "mirror".
2. At the point where it touches the mirror, draw a normal (a line perpendicular from the surface of the mirror).
3. Mark the angle between the arrow and the normal as 45 degrees (this is what the question tells us).
4. Because angle of incidence = angle of reflection, you can draw a second arrow on the OTHER side of the normal, beginning where the first arrow ended, that is also 45 degrees away from the normal.
5. The new arrow points in the direction the waves will travel after being reflected. You can draw blue lines back in, perpendicular to that new arrow, to show how the waves are moving after being reflected.
Hopefully that made sense but I can clarify if need be.