All categories

3 years ago

A cooling fan is turned off when it is running at 900 rev/min. It turns 1700 revolutions before it comes to a stop.

Physics

1 answer:

Degger [83]3 years ago

6 0

Answer:

a)α = - 0.415 rad/s²

b)t=226.68 sec

Explanation:

Given

Initial angular speed

ωi= 900 rev/min

$\omega_i=\dfrac{2\pi\times 900}{60}\ rad/s$

ωi= 94.24

θ = 1700 rev

We know that

1 rev = 2π rad

θ = 3400π rad

Final angular speed ωf=0 rad/s

α=Angular acceleration

We know that

ωf² = ωi²+ 2 α θ

0² = 94.24²+ 2 x 3400π x α

α = - 0.415 rad/s²

Negative sign indicates that acceleration and speed is in opposite direction.

We also know that

ωf = ωi+ α t

0 = 94.24 - 0.415 x t

t=226.68 sec

a)α = - 0.415 rad/s²

b)t=226.68 sec

You might be interested in

What can you say about the speed of light in diamond?

Inessa05 [86]

So n=c/v, n= index, c=speed of light and v= speed of light in diamond. 2.42=c/v so v=c/2.42, c≈3x108 m/sec so v=1.24x108 m/sec.
Hope this helps.

7 0

3 years ago

Over a span of 6.0 seconds, a car changes it's speed from 89 km/h to 37 km/h. What is its average acceleration in meters per sec

scoundrel [369]

Acceleration = (change in speed) / (time for the change)

change in speed = (speed at the end) - (speed at the beginning)

change in speed = (37 km/hr) - (89 km/hr) = -52 km/hr

Acceleration = (-52 km/hr) / (6 sec)

Acceleration = (-26/3) km/(hr·sec)

Units: (1/hr·sec) · (hr/3600 sec) = 1 / 3600 sec²

(-26/3) km/(hr·sec) = (-26/3) km/(3600 sec²)

= -26,000/(3 · 3600) m/s²

Acceleration = -2.41 m/s²

3 0

4 years ago

2 resistors of resistance 1000 ohm and 2000 ohm are joined in series with a 100V supply. A voltmeter of internal resistance 4000

Vadim26 [7]

<h2>The voltmeter reading will be 35.7 volt </h2>

Explanation:

The resistor 1000 ohm and 4000 ohm are connected in parallel .

Their combined resistance is supposed R₁

Thus $\frac{1}{R_1}$ = $\frac{1}{1000}$ + $\frac{1}{4000}$

or R₁ = 800 ohm

Therefore the total resistance in circuit is = 2000 + 800 = 2800 ohm

Because these are in series .

We can find current flowing through the circuit I = $\frac{V}{R}$ = $\frac{100}{2800}$ = $\frac{1}{28}$

here R is total resistance .

The potential difference across 1000 ohm = $\frac{1}{28}$ x 1000 = 35.7 volt

Thus voltmeter reading will be 35.7 volt

5 0

3 years ago

A 3 kilogram cat is resting on top of a bookshelf that is 1 meters high. What is the cat’s gravitational potential energy relati

AVprozaik [17]

We have: Gravitational Potential Energy (U) = mgh

Here, m = 3 Kg

g = 9.8 m/s² [ constant value for earth system ]

h = 3 m

Substitute their values into the expression:

U = 3 × 9.8 × 3

U = 88.2 J

In short, Your Answer would be 88.2 Joules

6 0

3 years ago

A toy cannon launches a 46-g golf ball straight up into the air with a kinetic energy of 6.8 J. What must the

Shkiper50 [21]

Answer : The correct option is, (C) 17 m/s

Explanation :

Formula used :

$K.E=\frac{1}{2}mv^2$

where,

K.E = kinetic energy = 6.8 J

m = mass of object = 46 g = 0.046 kg (1 kg = 1000 g)

v = velocity

Now put all the given values in the above formula, we get:

$K.E=\frac{1}{2}mv^2$

$6.8J=\frac{1}{2}\times 0.046kg\times v^2$

$6.8kg.m^2/s^2=\frac{1}{2}\times 0.046kg\times v^2$

$v=17.19m/s\approx 17m/s$

Therefore, the ball's velocity be as it leaves the cannon is, 17 m/s

3 0

3 years ago