1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Brilliant_brown [7]
3 years ago
13

A 1.15-kg grinding wheel 22.0 cm in diameter is spinning counterclockwise at a rate of 20.0 revolutions per second. When the pow

er to the grinder is turned off, the grinding wheel slows with constant angular acceleration and takes 80.0 s to come to a rest. (a) What was the angular acceleration (in rad/s2) of the grinding wheel as it came to rest if we take a counterclockwise rotation as positive?
Physics
2 answers:
malfutka [58]3 years ago
6 0

Answer:

Angular acceleration = -1.57 Rad/s^2

Number of revolutions = 800 revolutions

Explanation:

Mass = 1.15kg

diameter of the grinding wheel = 22.0cm

angular speed = 20 rev/s

1 Rev/s = 6.283 rad/s

20 Rev/s = 20 * 6.283 = 125.664 rad/s

Angular acceleration = Angular speed/ time taken for for the wheel rotation

Angular accleration = 125.664/80

Angular acceleration = -1.57 rad/s^2 (since the wheel is rotating counterclockwise)

number of revs = 0.5∝t²

number of revs = 0.5 * (1.57/2π) * 80²

number of revs = 800 revolutions

Oksi-84 [34.3K]3 years ago
4 0

Complete Question:

A 1.15-kg grinding wheel 22.0 cm in diameter is spinning counterclockwise at a rate of 20.0 revolutions per second. When the power to the grinder is turned off, the grinding wheel slows with constant angular acceleration and takes 80.0 s to come to a rest.

(a) What was the angular acceleration (in rad/s2) of the grinding wheel as it came to rest if we take a counterclockwise rotation as positive?

(b) How many revolutions did the wheel make during the time it was coming to rest?

Answer:

(a) the angular acceleration is -1.571 rad/s²

(b) the number of revolutions made by the wheel is 800 revolutions.

Explanation:

Given;

mass of the grinding wheel = 1.15 kg

diameter of the wheel = 22.0 cm

number of revolution = 20

time taken to come to rest = 80.0 s

Part (a) the angular acceleration (in rad/s2) of the grinding wheel as it came to rest if we take a counterclockwise rotation as positive.

\omega _f = \omega_i + \alpha t

where;

ωf is the final angular speed

ωi is the initial angular speed

α is the angular acceleration

\omega _f = \omega_i + \alpha t\\\\0 = (2\pi *20) + 80 \alpha\\\\ 80 \alpha = -40\pi \\\\\alpha = \frac{-40\pi}{80} = -1.571 \frac{rad}{s^2}

Part (b) number of revolutions the wheel made during the time it was coming to rest

\theta = \omega_i t+\frac{1}{2} \alpha t^2\\\\ \theta = \frac{1}{2}(\frac{1.571}{2\pi } ) (80)^2 = 800, revolutions

You might be interested in
PLEASE HELPP MEEE!!!!!!!!!The goal is to increase the power; therefore, it is necessary to
Brrunno [24]

As we know that power is defined as rate of work done

so we will have

P = \frac{Work}{time}

so in order to increase the power as per above formula we know that either we need to increase the work or we need to decrease the time to complete that work

So here the correct answer will be

increase the work being done or decrease the time in which the work is completed.

3 0
3 years ago
Read 2 more answers
if you are in Birmingham AL, and you want to use your cell phone to talk to your cousin in Houston, TX, what must occur in order
lesantik [10]

Answer:

For communication to be communicated between you and your cousin who is in Houston,Texas, when a call is made by you, a request is made to the specific phone, and the telephone tower will get the request from the mobile phone. Then a signal is sent via a transmitter underground, by this the satellite communicates with the local receiver in Houston, that is linked to the local tower over there, the tower would request for your cousin's number and connects the two of you, once a link is set.

Explanation:

From the example stated, what is required for such for a far distance, is a communication satellite link.

When a call is made by you, the a connection request is sent to the specified phone.The telephone tower receives the request from The mobile phone. The local tower(Birmingham,Al) is linked to a ground transmitter by the means of a Fiber optical cable.

A signal is sent to satellite via the ground transmitter.The satellite then set's off the local receiver in (Houston,Texas) which on it's end is connected to the local tower there. This tower then ask for your cousin's mobile for a call that will be incoming, a link is set, once he/she receives the call, from there a conversation can be done.

3 0
3 years ago
When you irradiate a metal with light of wavelength 433 nm in an investigation of the photoelectric effect, you discover that a
sergij07 [2.7K]

Answer:

The right solution is:

(a) 2.87 eV

(b) 1.4375 eV

Explanation:

Given:

Wavelength,

= 433 nm

Potential difference,

= 1.43 V

Now,

(a)

The energy of photon will be:

E = \frac{6.626\times 10^{-34}\times 3\times 10^8}{433\times 10^{-9}}

  = 4.59\times 10^{-19} \ J

or,

  = \frac{4.59\times 10^{-19}}{1.6\times 10^{-19}}

  = 2.87 \ eV

(b)

As we know,

⇒ Vq=\frac{hc}{\lambda}-\Phi_0

By substituting the values, we get

⇒ 1.43\times 1.6\times 10^{19}=\frac{6.626\times 10^{-34}\times 3\times 10^8}{433\times 10^{-9}}-\Phi_0

⇒                       \Phi_0=2.3\times 10^{-19} \ J

or,

⇒                            =\frac{2.3\times 10^{-19}}{1.6\times 10^{-19}}

⇒                            =1.4375 \ eV

5 0
3 years ago
How much heat Q H QH does a heat pump with a coefficient of performance of 2.10 2.10 deliver when supplied with 1.82 kJ 1.82 kJ
valina [46]

The operating coefficient or performance coefficient of a heat pump is the ratio between the heating or cooling provided and the electricity consumed. The higher coefficients are equivalent to lower operating costs. The coefficient can be greater than 1, because it is a percentage of the output: losses, other than the thermal efficiency ratio: input energy. Mathematically can be written as,

\text{Coefficient of performance} = \frac{\text{Heat extracted}}{\text{Electrical energy supplied}}

COP = \frac{Q}{E}\rightarrow Q =COP\times E

Replacing,

Q = 2.1\times 1.82kJ

Q = 3.822kJ

Therefore the heat is 3.822kJ

4 0
2 years ago
If you put 120 volts of electricity through a pickle, the pickle will smoke and start glowing orange-yellow. The light is emitte
Alona [7]

Answer:

2.11eV

Explanation:

We know that speed of light is it's wavelength times frequency.

\therefore f=v/\lambda\\=(3\times10^8m/s)/(589mm\times1m/1\times 10^9nm)\\=5.09\times10^1^4s^-1 \ or \ 5.09\times10^1^4Hz

Planck's constant is 6.626\times 10^3^4Js

The energy gap is calculated by multyplying the light's frequency by planck's constant:

E_c=5.09\times10^1^4s^-^1\times 6.626\times10^-^3^4Js\\\\=3.37\times 10^-^1^9J  \ \ \ \ \ \ #1eV=1.06\times 10^-^1^9J\\\\=2.11eV

Hence, the energy gap is 2.11eV

4 0
3 years ago
Other questions:
  • The three classes of rocks are sedimentary, metamorphic, and igneous. How are rocks classified into one of these three groups? A
    11·2 answers
  • As temperature increases what energy decreases
    10·1 answer
  • Which layers of the earth are considered liquid a) crust b) inner corec) outer core d) lower mantle
    8·1 answer
  • The rate constant for this first‑order reaction is 0.150 s−1 at 400 ∘C. A⟶products How long, in seconds, would it take for the c
    13·1 answer
  • A decrease in the height of a column in a mercury barometer means that _____. air pressure is increasing wind speed is increasin
    7·2 answers
  • A motorboat embarks on a trip, heading downstream in a river in which the current flows at a rate of 1.5m/s. After 30.0 minutes,
    6·1 answer
  • Q
    13·1 answer
  • What type of charge is used as the test charge to determine the direction of electric fields?
    10·1 answer
  • At 10 seconds, you used 55 Joules. Can you tell me the power?
    15·2 answers
  • This table shows the weights of four different objects that are sitting on the
    6·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!