Answer:
F = 48 [N]
Explanation:
To solve this problem we must use Newton's third law, which tells us that the sum of forces on a body must be equal to zero, that is, the body is in static equilibrium or in equilibrium.
ΣF = 0
24 + 24 - F = 0
F = 24 + 24
F = 48 [N]
Note: Jeff's force should be equal to the sum of Sally and Misha's forces, but in the opposite direction.
The given question is incomplete. The complete question is as follows.
The irregularly shaped area of charge in the figure has surface charge density ηi. Each dimension (x and y) of the area is reduced by a factor of 3.68.
What is the ratio ηf/ηi where ηf is the final surface charge density? I found this value to be 13.5 and it is correct
An electron is very far from the area. What is the ratioFf/Fi of the electric force on the electronafter the area is reduced to the force before the area wasreduced? I found this to also be 13.5, but it is wrong.
Explanation:
Let us consider that expression for area will be as follows.
Area () =
As,
= 13.5
Also, = 1
As the electron is very far from the area. Hence, it can be considered as a point charge. Whereas charge is also constant as the force is not changing.
Answer:
The original volume of the first bar is half of the original volume of the second bar.
Explanation:
The coefficient of cubic expansivity of substances is given by;
γ = ΔV ÷ (Δθ)
Given: two metal bars with equal change in volume, equal change in temperature.
Let the volume of the first metal bar be represented by , and that of the second by .
Since they have equal change in volume,
Δ = Δ = ΔV
For the first metal bar,
2γ = ΔV ÷ (Δθ)
⇒ Δθ = ΔV ÷ (2γ)
For the second metal bar,
γ = ΔV ÷ (Δθ)
⇒ Δθ = ΔV ÷ (γ)
Since they have equal change in temperature,
Δθ of first bar = Δθ of the second bar
ΔV ÷ (2γ) = ΔV ÷ (γ)
So that;
(1 ÷ 2) = (1 ÷ )
2 =
=
Thus, original volume of the first bar is half of the original volume of the second bar.
Answer:
The Magnetic field is 59.13 mT.
Explanation:
Given that,
Number of turns = 400
Radius = 1.0 cm
Frequency = 90 Hz
Emf = 4.2 V
We need to calculate the angular velocity
Using formula of angular velocity
We need to calculate the magnetic flux
Relation between magnetic flux and induced emf
Put the value into the formula
Hence, The Magnetic field is 59.13 mT.
Answer:
a) 65 N
b) Each initially applied a force bigger than static friction to get the box moving and accelerating, then when the desired final speed was achieved they reduced the force to make the net force zero.
Explanation:
a) Here, both boxes are identical. They have different velocities but the velocities are constant hence the force Alice is applying is 65 N. Constant velocity means there is no acceleration.
b) The acceleration that Alice provided must have been different than that of Bob. But after reaching their desired speed they stopped accelerating. This would make the net force zero.