Answer:
1 N
Explanation:
From coulomb's law,
The force of attraction between two charges is inversely proportional to the square of the distance between the charges.
From the question,
Assuming the charges are the same in both case,
F ∝ /r²....................... Equation 1
Fr² = k
F'r'² = Fr²........................... Equation 2
Where F' = First Force, r'² = First distance, F = second force, r² = second distance.
make F the subject of the equation,
F = F'r'²/r².................... Equation 3
Given: F' = 4 N, r' = 3 m, r = 6 m
Substitute into equation 3
F = 4(3²)/6²
F = 36/36
F = 1 N
Explanation:
It is given that,
The mass of bob, m = 77 kg
Length of the string, L = 10 m
Angle made by the string with the vertical, 
(a) Let T is the force exerted by the string on the pendulum. At equilibrium,



T = 755.63 N
The horizontal component of the force is given by,


The vertical component of the force is given by,


(b) Let a is the radial acceleration of the bob. It can be calculated as :



Hence, this is the required solution.
Answer:
suvat is an acronym of five variables that describe a system in motion. a, s, u, v and t
Answer: 178.25*10^-6 T
Explanation: In order to solve this problem we have to take into account the equilibrium between the electric and magnetic forces in the electron, so it is given by:
Fm=evB
Fe=eE so
evB=eE the we have
v=E/B
Firsly we calculate the velocity of the electron before to get the parallel plates at 100V
eΔV=1/2*m*v^2 then
v=(2*eΔV/m)^1/2
v=(2*1.6*10^-19*3.1*10^3/9.1*10^-31)^1/2=33 *10^6 m/s
Then we can calculate B
B=E/v E.d=V where d is the separation between the plates and V is equal a 100V
B=V/(d*v)=100/(17*10^-3*33 *10^6)=178.25*10^-6 T
The mass of a is smaller than the mass of b.