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
antoniya [11.8K]
3 years ago
12

A cd has a mass of 17 g and a radius of 6.0 cm. When inserted into a player, the cd starts from rest and accelerates to an angul

ar velocity of 21 rad / s in 0.8s, assuming the cd is a uniform solid disk. a) Determine the sum of the net torque action on it.
Physics
1 answer:
GuDViN [60]3 years ago
3 0

Answer:

the net toque is τ=8.03* 10⁻⁴ N*m

Explanation:

Assuming the disk has constant density ρ, the moment of inertia I of is

I = ∫r² dm

since m = ρ*V = ρπR² h , then dm= 2ρπh r dr

thus

I = ∫r²dm = ∫r²2ρπh r dr =2ρπh ∫r³ dr = 2ρπh (R⁴/4- 0⁴/4)= ρπhR⁴ /2= mR²/2

replacing values

I = mR²/2= 0.017 kg * (0.06 m)²/2 = 3.06 *10⁻⁵ kg*m²

from Newton's second law applied to rotational motion

τ= Iα , where τ=net torque and α= angular acceleration

since the angular velocity ω is related with the angular acceleration through

ω= ωo + α*t → α =(ω-ωo)/t =  (21 rad/s-0)/0.8 s = 26.25 rad/s²

therefore

τ= Iα= 3.06 *10⁻⁵ kg*m²*26.25 rad/s² = 8.03* 10⁻⁴ N*m

You might be interested in
Please, pretty please help me!
Andrews [41]

Answer:

umm

Explanation:

1223565 578633 =334675

8 0
2 years ago
Read 2 more answers
During a braking test, a car is brought to rest beginning from an initial speed of 60 mi/hr in a distance of 120 ft. With the sa
maw [93]

Answer:

Explanation:

Given

Initial speed u=60\ mi/hr\approx 88\ ft/s

distance traveled before coming to rest d_1=120\ ft

using equation of motion

v^2-u^2=2as

where v=final velocity

u=initial velocity

a=acceleration

s=displacement

0-(88)^2=2\times a\times 120---1

for u_2=80\ mi/hr\approx 117.33\ ft/s

using same relation we get

0-(117.33)^2=2\times a\times (d_2)----2

divide 1 and 2 we get

(\frac{88}{117.33})^2=\frac{120}{d_2}

d_2=213.32\ ft

So a distance if 213.32 ft is required to stop the vehicle with 80 mph speed

8 0
3 years ago
Study the analogy, and then answer the question that follows.
nordsb [41]
What kind of analogy is this?
A. synonyms
B. part to whole
C. degrees of intensity
<span>D. cause to effect
This is because a synonym refers to things like "normal" or  "regular" like your calling someone something.
</span><span /><span>
</span>
6 0
3 years ago
Read 2 more answers
What happens to the mass and to the weight of the foam rubber when it is compressed?​
Orlov [11]

Answer:

423523523523

Explanation:

52334W53WR53WRRWRW35423

4 0
2 years ago
Read 2 more answers
A marshmallow is dropped from a 5.71 meter high pedestrian bridge, and 0.921 seconds later, it lands right on the head of an uns
Natalka [10]

let the height of the person with marshmallow on her head be "h"

consider the motion of the marshmallow after it is dropped from bridge.

Y₀ = initial position of the marshmallow above the ground = 5.71 m

Y = final position of marshmallow on head of person = h

v₀ = initial velocity of the marshmallow = 0 m/s

a = acceleration due to gravity = - 9.8 m/s²

t = time of travel for marshmallow = 0.921 sec

Using the kinematics equation

Y = Y₀ + v₀ t + (0.5) a t²

inserting the values

h = 5.71 + 0 (0.921) + (0.5) (-9.8) (0.921)²

h = 5.71 - 4.16

h = 1.55 m

5 0
3 years ago
Other questions:
  • A place or object used for comparison to determine if something is moving
    7·1 answer
  • Explain three ways you can get home safely, without getting behind the wheel, if there are drugs or alcohol in your system.
    13·1 answer
  • A gaseous system undergoes a change in temperature and volume. What is the entropy change for a particle in this system if the f
    11·1 answer
  • 9. The three types of stress that act on Earth's rocks are compression, tension, and A. strain. B. shear. C. tephra. D. shale.
    13·2 answers
  • Newton's law of gravity was inconsistent with Einstein's special relativity because
    9·1 answer
  • A burning candle provides :
    15·1 answer
  • Say what main energy change
    10·1 answer
  • A person tries to lift each object with a force of 25 N, upward. Which
    13·2 answers
  • DNA ___ occurs during the s phase of Interphase.
    8·1 answer
  • If the forces on an object are greater than zero, the motion of an object will what?
    10·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!