Answer:
Mass of the oil drop, 
Explanation:
Potential difference between the plates, V = 400 V
Separation between plates, d = 1.3 cm = 0.013 m
If the charge carried by the oil drop is that of six electrons, we need to find the mass of the oil drop. It can be calculated by equation electric force and the gravitational force as :
, e is the charge on electron
E is the electric field, 
So, the mass of the oil drop is 
. Hence, this is the required solution.
if rebecca stands in front of david at a distance of do and david perceives the position of rebecca at di, di will be +84 cm
<h3>What is focal length ?</h3>
How strongly light converges or diverges depends on an optical system's focal length, which is the inverse of optical power. A system with a positive focus length is said to converge light, whereas one with a negative focal length is said to diverge light.
focal length = +60 cm
magnification m = -0.40
focal length being positive an magnification negative.
given lens is a convex lens.
for a lens
m = di/do and 1/f = (1/di) - (1/do)di
= -0.4do1/f = (1/-0.4do) - 1/do do
= -210 cmdi = -0.4 * -210
di = +84 cm
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Answer:
A u = 0.36c B u = 0.961c
Explanation:
In special relativity the transformation of velocities is carried out using the Lorentz equations, if the movement in the x direction remains
u ’= (u-v) / (1- uv / c²)
Where u’ is the speed with respect to the mobile system, in this case the initial nucleus of uranium, u the speed with respect to the fixed system (the observer in the laboratory) and v the speed of the mobile system with respect to the laboratory
The data give is u ’= 0.43c and the initial core velocity v = 0.94c
Let's clear the speed with respect to the observer (u)
u’ (1- u v / c²) = u -v
u + u ’uv / c² = v - u’
u (1 + u ’v / c²) = v - u’
u = (v-u ’) / (1+ u’ v / c²)
Let's calculate
u = (0.94 c - 0.43c) / (1+ 0.43c 0.94 c / c²)
u = 0.51c / (1 + 0.4042)
u = 0.36c
We repeat the calculation for the other piece
In this case u ’= - 0.35c
We calculate
u = (0.94c + 0.35c) / (1 - 0.35c 0.94c / c²)
u = 1.29c / (1- 0.329)
u = 0.961c
