Answer:
B)
Explanation:
The electric force between charges can be determined by;
F =
Where: F is the force, k is the Coulomb's constant, is the value of the first charge,
is the value of the second charge, r is the distance between the centers of the charges.
Let the original charge be represented by q, so that;
= 2q
=
So that,
F = x
= 2q x x
= x
= x
F = x
The electric force between the given charges would change by .
Answer:
Length = 2.32 m
Explanation:
Let the length required be 'L'.
Given:
Resistance of the resistor (R) = 3.7 Ω
Radius of the rod (r) = 1.9 mm = 0.0019 m [1 mm = 0.001 m]
Resistivity of the material of rod (ρ) =
First, let us find the area of the circular rod.
Area is given as:
Now, the resistance of the material is given by the formula:
Express this in terms of 'L'. This gives,
Now, plug in the given values and solve for length 'L'. This gives,
Therefore, the length of the material required to make a resistor of 3.7 Ω is 2.32 m.
Answer:
0.76
Explanation:
we are given:
radius (r) =5.7 m
speed (s) = 1 revolution in 5.5 seconds
acceleration due to gravity (g) = 9.8 m/s^{2}
coefficient of friction (Uk) = ?
we can get the minimum coefficient of friction from the equation below
centrifugal force = frictional force
m x r x ω^{2} = Uk x m x g
r x ω^{2} = Uk x g
Uk =
where ω (angular velocity) =
= = 1.14
Uk = = 0.76