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
dimaraw [331]
3 years ago
9

While spinning down from 500 rpm to rest, a flywheel does 3.9 kj of work. this flywheel is in the shape of a solid uniform disk

of radius 1.2 m. what is the mass of this flywheel?
Physics
1 answer:
Ksivusya [100]3 years ago
6 0

 

The answer is 4.0 kg since the flywheel comes to rest the kinetic energy of the wheel in motion is spent doing the work. Using the formula KE = (1/2) I w².

Given the following:

I =  the moment of inertia about the axis passing through the center of the wheel; w = angular velocity ; for the solid disk as I = mr² / 2 so KE = (1/4) mr²w². Now initially, the wheel is spinning at 500 rpm so w = 500 * (2*pi / 60) rad / sec = 52.36 rad / sec.

The radius = 1.2 m and KE = 3900 J

3900 J = (1/4) m (1.2)² (52.36)²

m = 3900 J / (0.25) (1.2)² (52.36)²

m = 3.95151 ≈ 4.00 kg

You might be interested in
An airplane touches down on the runway with a speed of 70 m/s2. Determine the airplane after each second of its deceleration.
ivann1987 [24]
<span>vf^2 = vi^2 + 2*a*d
---
vf = velocity final
vi = velocity initial
a = acceleration
d = distance
---
since the airplane is decelerating to zero, vf = 0
---
0 = 55*55 + 2*(-2.5)*d
d = (-55*55)/(2*(-2.5))
d = 605 meters


</span>
5 0
3 years ago
Why in a rollercoaster the height of the tracks is either equal to or less than the first track
umka2103 [35]

Answer:

I really don't know

Explanation:

sorry

6 0
2 years ago
In order to determine the velocity, you must know
Naddik [55]
You need to know the speed and direction of object
5 0
3 years ago
Read 2 more answers
Light striking a mirror at a 50° angle will be reflected at an angle _____.
Stells [14]
Equal to 50


law of reflection: angle of incidence equals angle of reflection
5 0
3 years ago
Read 2 more answers
Which of the following statements are true?
inessss [21]

Answer:

a. If an object's speed is constant, then its acceleration must be zero.

FALSE

As we know that acceleration is defined as the rate of change in velocity

a = \frac{d\vec v}{dt}

so we can not say anything about the acceleration when speed is given to as and no information is given about velocity

b. If an object's acceleration is zero, then its speed must be constant.

TRUE

As we know that acceleration is defined as the rate of change in velocity

a = \frac{d\vec v}{dt}

Since we know that if acceleration is 0 then velocity must be constant and hence speed is also constant

c. If an object's velocity is constant, then its speed must be constant.

TRUE

Since velocity is constant then it shows that its magnitude and direction both are constant so its speed is also constant.

d. If an object's acceleration is zero, its velocity must be constant.

TRUE

As we know that acceleration is defined as the rate of change in velocity

a = \frac{d\vec v}{dt}

Since we know that if acceleration is 0 then velocity must be constant

e. If an object's speed is constant, then its velocity must be constant.

FALSE

Speed is just the magnitude so we can not say about its direction and hence if speed is constant then velocity may or may not change

7 0
3 years ago
Other questions:
  • Compute the resistance of a hardened copper rod 2 meters long and 8 mm in diameter if resistivity of the material is 1.756 x 10^
    13·1 answer
  • Yellow light is incident upon a medium from air at an angle of 45.0°. The light bends toward the normal and refracts at 28.0°. W
    9·2 answers
  • During circular motion, the force that is perpendicular to the velocity and toward the center of the circle is the ... ?
    12·1 answer
  • Use Kepler’s third law and the orbital motion of Earth to determine the mass of the Sun. The average distance between Earth and
    7·2 answers
  • A sample of Bismuth-212 has a mass of 2.64 grams (g) after 121 seconds (s). What was the initial mass of the sample if Bismuth-2
    11·1 answer
  • A 5 meter long ladder leans against a wall. The bottom of the ladder slides away from the wall at the constant rate of 1 3 m/s.
    5·1 answer
  • As a 2-kg ball rolls down a ramp, the net force on it is 10 N. What is the acceleration?
    9·1 answer
  • How is sound created (at the particle level)?
    8·1 answer
  • Please helpp!! Questions 1-5
    7·1 answer
  • A baseball pitcher throws a fastball with a 100 ns impulse. if he applied the force in 0. 15 seconds, what force did he apply?
    10·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!