Question

21. Listening is a effort by the
receiver to perceive and understand
the message. *
Ounconscious
O conscious
Ouniversal
O passive
This is a required question​

Answer 1

Answer:

Answer:

The work done by the moon when it revolves around the earth is zero because here displacement of moon and gravitational force of earth are perpendicular to each other.

i.e., Work done (W) =F×d×cosθ

where F = applied force

d = displacement of the body

θ = angle between the applied force and the displacement of the body

In the case of revolution of moon around the earth, θ is 90°. Thus, W=F×d×cos90°

 = F×d×0=0

So, the work done by the moon when it revolves around the earth is zero.

Answered ByAnswer:

Angular retardation of flywheel = π/10  rad/s²

Explanation:

Given:-

Initial angular velocity of flywheel = 360 rpm

Final angular velocity of flywheel = 180 rpm

Time taken for change in angular velocity = 1 min = 60 sec

To find:-

Angular acceleration (retardation) of the flywheel, a =?

Formula required:-

Formula for angular acceleration

        a = Δω / Δt

[ where a is angular acceleration, Δω is change in angular velocity, Δt is change in time ]

Solution:-

Converting the angular velocities given in rpm into rad/sec

→ ω₁ = 360 rpm = 360 × 2π/60  rad/sec = 12π rad/sec

→ ω₂ = 180 rpm = 180 × 2π/60  rad/sec = 6π rad/sec

Calculating the angular acceleration

→ a = Δω / Δt

→ a = (12π - 6π) / (60)

→ a = -6π / 60

→ a = -π/10  rad/s²

Therefore,

Angular retardation of the flywheel is π/10  rad/s².

A computer is an electronic machine that was invented by Charles babage