Answer:
α = (ω²)/8π
Explanation:
The angular acceleration(α) of the carousel can be determined by using rotational
kinematics:
ω² =ωo² + 2αθ
Let's make α the subject of this equation ;
ω² - ωo² = 2αθ
α = (ω² −ωo²)/2θ
Now, from the question, since initially at rest, thus, ωo = 0
Also,since 2 revolutions, thus, θ = 2 x 2π = 4π since one revolution is 2π
Plugging in the relevant values to get ;
α = (ω²)/2(4π)
α = (ω²)/8π
Answer:
210.3 degrees
Explanation:
The net force exerted on charge A = 59.5 N
Use the x and y coordinates of net force to get the direction
arctan (y/x)
Answer:
Temperature decreases because the number of collision of the molecules decreases as they escape or evaporate. Molecules are in constant motion. Increase in temperature leads to increase in average kinetic energy of the molecules.
Answer:

Explanation:
Torque is defined as the cross product between the position vector ( the lever arm vector connecting the origin to the point of force application) and the force vector.

Due to the definition of cross product, the magnitude of the torque is given by:

Where
is the angle between the force and lever arm vectors. So, the length of the lever arm (r) is minimun when
is equal to one, solving for r:

As the question is about changing in frequency of a wave for an observer who is moving relative to the wave source, the concept that should come to our minds is "
Doppler's effect."
Now the general formula of the Doppler's effect is:

-- (A)
Note: We do not need to worry about the signs, as everything is moving towards each other. If something/somebody were moving away, we would have the negative sign. However, in this problem it is not the issue.
Where,
g = Speed of sound = 340m/s.

= Velocity of the receiver/observer relative to the medium = ?.

= Velocity of the source with respect to medium = 0 m/s.

= Frequency emitted from source = 400 Hz.

= Observed frequency = 408Hz.
Plug-in the above values in the equation (A), you would get:


Solving above would give you,

= 6.8 m/s
The correct answer = 6.8m/s