Answer:
a. +10.9μC
b. 0.600N and downward
Explanation:
To determine the magnitude of the charge, we use the force rule that exist between two charges which us expressed as
F=(kq₁q₂)/r²
since q₁=-0.55μC and the force it applied on the charge above it is upward,we can conclude that the second charge is +ve, hence we calculate its magnitude as
q₂=Fr²/kq₁
q₂=(0.6N*0.3²)/(9*10⁹*0.55*10⁻⁶)
q₂=0.054/4950
q₂=1.09*10⁻⁵c
q₂=10.9μC.
Hence the second charge is +10.9μC
b. From the rule of charges which state that like charges repel and unlike charges attract, we can conclude that the two above charges will attract since they are unlike charges. Hence the direction of the force will be downward into the second charge and the magnitude of the force will remain the same as 0.600N
Answer:
F=8.0*10^{-10}N
Explanation:
See the attached file for the masses distributions
The force between two masses at distance r is expressed as

since the masses are of the same value, the above formula can be reduce to

using vector notation,Let use consider the force on the lower left corner of the mass due to the upper left side of the mass is

The force on the lower left corner of the mass due to the lower right side of the mass is

The force on the lower left corner of the mass due to the upper right side of the mass is

The net force can be express as
![F=\frac{Gm^{2}}{r^{2} }j +\frac{Gm^{2}}{r^{2} }i +\frac{Gm^{2}}{d^{2} }cos\alpha i +\frac{Gm^{2}}{d^{2} }sin\alpha j\\\\F=Gm^{2}[\frac{1}{r^{2}}+ \frac{1}{d^{2}cos\alpha }]i + Gm^{2}[\frac{1}{r^{2}}+ \frac{1}{d^{2}sin\alpha }]j\\\alpha=45^{0}, G=6.67*10^{-11}Nmkg^{-2}](https://tex.z-dn.net/?f=F%3D%5Cfrac%7BGm%5E%7B2%7D%7D%7Br%5E%7B2%7D%20%7Dj%20%2B%5Cfrac%7BGm%5E%7B2%7D%7D%7Br%5E%7B2%7D%20%7Di%20%2B%5Cfrac%7BGm%5E%7B2%7D%7D%7Bd%5E%7B2%7D%20%7Dcos%5Calpha%20i%20%2B%5Cfrac%7BGm%5E%7B2%7D%7D%7Bd%5E%7B2%7D%20%7Dsin%5Calpha%20j%5C%5C%5C%5CF%3DGm%5E%7B2%7D%5B%5Cfrac%7B1%7D%7Br%5E%7B2%7D%7D%2B%20%5Cfrac%7B1%7D%7Bd%5E%7B2%7Dcos%5Calpha%20%7D%5Di%20%2B%20Gm%5E%7B2%7D%5B%5Cfrac%7B1%7D%7Br%5E%7B2%7D%7D%2B%20%5Cfrac%7B1%7D%7Bd%5E%7B2%7Dsin%5Calpha%20%7D%5Dj%5C%5C%5Calpha%3D45%5E%7B0%7D%2C%20G%3D6.67%2A10%5E%7B-11%7DNmkg%5E%7B-2%7D)
if we insert values we arrive at
![F=6.67*10^{-11}*2.5^{2}[\frac{1}{1^{2}}+ \frac{1}{\sqrt{2}^{2}cos45 }]i + 6.67*10^{-11}*2.5^{2}[\frac{1}{1^{2}}+ \frac{1}{\sqrt{2}^{2}sin45}]j\\F=5.643*10^{-10}i+5.643*10^{-10}j](https://tex.z-dn.net/?f=F%3D6.67%2A10%5E%7B-11%7D%2A2.5%5E%7B2%7D%5B%5Cfrac%7B1%7D%7B1%5E%7B2%7D%7D%2B%20%5Cfrac%7B1%7D%7B%5Csqrt%7B2%7D%5E%7B2%7Dcos45%20%7D%5Di%20%2B%206.67%2A10%5E%7B-11%7D%2A2.5%5E%7B2%7D%5B%5Cfrac%7B1%7D%7B1%5E%7B2%7D%7D%2B%20%5Cfrac%7B1%7D%7B%5Csqrt%7B2%7D%5E%7B2%7Dsin45%7D%5Dj%5C%5CF%3D5.643%2A10%5E%7B-10%7Di%2B5.643%2A10%5E%7B-10%7Dj)
if we solve for the magnitude, we arrive at

Hence the net force on one of the masses is

2. random motion in vertical direction
Answer:
Laterite would be your answer.
Explanation:
I hope this helps!
Answer:
v = 10 m/s
Explanation:
Let's assume the wheel does not slip as it accelerates.
Energy theory is more straightforward than kinematics in my opinion.
Work done on the wheel
W = Fd = 45(12) = 540 J
Some is converted to potential energy
PE = mgh = 4(9.8)12sin30 = 235.2 J
As there is no friction mentioned, the remainder is kinetic energy
KE = 540 - 235.2 = 304.8 J
KE = ½mv² + ½Iω²
ω = v/R
KE = ½mv² + ½I(v/R)² = ½(m + I/R²)v²
v = √(2KE / (m + I/R²))
v = √(2(304.8) / (4 + 0.5/0.5²)) = √101.6
v = 10.07968...