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
BlackZzzverrR [31]
3 years ago
13

A firm wants to determine the amount of frictional torque in their current line of grindstones, so they can redesign them to be

more energy efficient. To do this, they ask you to test the best-selling model, which is basically a diskshaped grindstone of mass 2.0 kg and radius 9.90 cm which operates at 720 rev/min. When the power is shut off, you time the grindstone and find it takes 41.9 s for it to stop rotating.
(a) What is the angular acceleration of the grindstone in rad/s^2? (b) What is the frictional torque exerted on the grindstone in N·m?
Physics
1 answer:
victus00 [196]3 years ago
8 0

Answer:

a)- 1.799 rad/sec²

b)- 17.6 x 10ˉ³Nm

Explanation:

ω₀ = 720 rev/min x (1 min/60 sec) x (2π rad / 1 rev) =  24π rad/s

a) Assuming a constant angular acceleration, the formula will be

α = (ωf -ω₀) / t

As final state of the grindstone is at rest, so ωf =0

⇒ α = (0-24π) / 41.9 = - 1.799 rad/sec²

b)Moment of inertia I for a disk about its central axis

I = ½mr²  

where m=2kg and radius 'r'= 0.099m

I = ½(2)(0.099²)

I = 9.8 x 10ˉ³ kgm²

Next is to determine the frictional torque exerted on the grindstone, that caused it to stop, applying the rotational equivalent of the Newton's 2nd law:

τ = I α =>(9.8 x 10ˉ³)(- 1.799)

τ = - 17.6 x 10ˉ³Nm

(The negative sign indicates that the frictional torque opposes to the rotation of  the grindstone).

You might be interested in
You drag a suitcase of mass 8.2 kg with a force of f at an angle 41.9 ◦ with respect to the horizontal along a surface with kine
DedPeter [7]

Answer:

35.6 N

Explanation:

We can consider only the forces acting along the horizontal direction to solve the problem.

There are two forces acting along the horizontal direction:

- The horizontal component of the pushing force, which is given by

F_x = F cos \theta

with \theta=41.9^{\circ}

- The frictional force, whose magnitude is

F_f = \mu mg

where \mu=0.33, m=8.2 kg and g=9.8 m/s^2.

The two forces have opposite directions (because the frictional force is always opposite to the motion), and their resultant must be zero, because the suitcase is moving with constant velocity (which means acceleration equals zero, so according to Newton's second law: F=ma, the net force is zero). So we can write:

F_x - F_f=0\\F_x = F_f\\F cos \theta = \mu mg\\F=\frac{\mu mg}{cos \theta}=\frac{(0.33)(8.2 kg)(9.8 m/s^2)}{cos(41.9^{\circ})}=35.6 N

8 0
3 years ago
The forces acting on this object are _______ and the net force is ________ Balanced, 0 N Balanced, 10 N Unbalanced, 10 N Unbalan
Amanda [17]
1st Blank Answer: Balanced   
2nd Blank Answer: 0n 

I took the test and got it right
I would appreciate a Brainliest...
5 0
3 years ago
Read 2 more answers
Which phrase best describes a metallic bond?
aalyn [17]
Metallic bonding<span> is the force of attraction between valence electrons and the metal ions. It is the sharing of many detached electrons between many positive ions, 
 
                           Hopefully this can help you understand

</span>
6 0
3 years ago
Read 2 more answers
ILL MARK BRAINIEST IF YOU DO THIS CORRECTLY!!!
IRINA_888 [86]

Explanation:

1)5.8m/s

2)5.15m/s^2

3)12.69m/s

4)

8 0
3 years ago
________ Is a push or pull
victus00 [196]

Answer:

lever

Explanation:

because you can push and pull a lever

5 0
2 years ago
Other questions:
  • Tarzan swings back and forth on a long vine with a period of 7.27 s. how long is the vine?(unit=m)
    9·1 answer
  • Answer the following question: “Do the particles in a gas ever slow down and stop? Include information about the three states of
    8·1 answer
  • Laws that implemented the consumers' right to be informed forbid __________.
    12·2 answers
  • A cast iron paperweight is in the shape of a half-sphere with a diameter of 8.2cm. The cast iron has a density of 7.3g/cm^3. Wha
    10·1 answer
  • An object moves in simple harmonic motion described by the equation d equals one fifth sine 2 t where t is measured in seconds a
    9·1 answer
  • Blue light (λ = 475 nm) is sent through a single slit with a width of 2.1 µm. What is the maximum possible number of bright frin
    7·1 answer
  • T object]user: if you have a diagnostic x-ray, then you have been:
    11·2 answers
  • 11. (a)What downward force is acting on you when you go down a waterslide? (b)What type of friction is
    11·1 answer
  • A block is pulled across a table by a constant force of 9.20 N. If the mass of the block is 2.30kg, how fast will the block be m
    10·1 answer
  • The force that causes an object to follow a
    11·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!