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
Ivanshal [37]
3 years ago
7

A propeller is modeled as five identical uniform rods extending radially from its axis. The length and mass of each rod are 0.82

7 m and 2.89 kg, respectively. When the propeller rotates at 507 rpm (revolutions per minute), what is its rotational kinetic energy K
Physics
1 answer:
melisa1 [442]3 years ago
4 0

Answer:

3241.35J

Explanation:

No. Of rods = 5

Mass = 2.89kg

Length (L) = 0.827m

W = 507rpm

Kinetic energy of rotation = ½I*ω²

For each rod, the moment of inertia (I) = ML² / 3

I = ML² / 3

I = [2.89*(0.827)²] / 3

I = 1.367 / 3 = 0.46kgm²

ω = 507 rev/min. Convert rev/min to rev/sec.

507 * 2Πrads/60s = 53.09rad/s

ω = 53.09rad/s

k.e = ½ I * ω²

K.E = ½ * 0.46 * (53.09)²

K.E = 648.27.

But there five (5) rods, so kinetic energy is equal to

K.E = 5 * 648.27 = 3241.35J

You might be interested in
HELP
dem82 [27]

Answer:

Explanation:

28 / 70 = 0.3857142...  = 0.39 hr

280 / 100 = 2.8 hrs.

(100 - 0) / 10 = 10 m/s²

(60 - 20) / 4 = 10 m/s²

3 0
2 years ago
A crowbar 2727 in. long is pivoted 66 in. from the end. What force must be applied at the long end in order to lift a 600600 lb
NikAS [45]

To solve this problem we will apply the concepts related to equilibrium, for this specific case, through the sum of torques.

\sum \tau = F*d

If the distance in which the 600lb are applied is 6in, we will have to add the unknown Force sum, at a distance of 27in - 6in will be equivalent to that required to move the object. So,

F*(27-6)= 6*600

F = \frac{6*600}{21}

F= 171.42 lb

So, Force that must be applied at the long end in order to lift a 600lb object to the short end is 171.42lb

4 0
3 years ago
Why do cells have receptors? Receptors make mRNA. Receptors let the cell know when to let things in and out of the cell. Recepto
Pavlova-9 [17]

Answer: Cells have receptors because Receptors let the cell know when to let things in and out of the cell.

Explanation:

Cell receptors also called transmembrane receptors are proteins located on the surface of a cell (extracellularly) or inside the cell which receive signals that alters the functions of the cell. The functions of the cells which can be altered includes the alteration in gene transcription and the cell morphology.

Cell receptors are generally categorizes into the following groups:

--> Internal receptors

--> cell surface receptors

--> ion channel receptors

--> G protein coupled receptors

--> enzyme linked receptors

Interaction of cell membrane receptors with specific ligands that bonds to the receptors causes conformational changes in the receptor protein. This in turn, enzymatically activates the intracellular part of the protein or induces interactions between the receptor and the proteins in the cytoplasm that act as second messengers, thereby relaying the signal from the extracellular part of the receptor to the interior of the cell. This enables the cell to know when to let things in or out of it through the information conveyed.

6 0
2 years ago
Which of the following is true about light?
ale4655 [162]
Light travels in waves AND in bundles called "photons".

It's hard to imagine something that's a wave and also a bundle.
But it turns out that light behaves like both waves and bundles.

If you design an experiment to detect waves, then it responds to light.

And if you design an experiment to detect 'bundles' or particles, then
that one also responds to light.
7 0
3 years ago
In moving out of a dormitory at the end of the semester, a student does 1.82 x 104 J of work. In the process, his internal energ
emmainna [20.7K]

Answer:

Explanation:

(a) Work done, W = 1.82 x 10^4 J

(b) internal energy, U = - 4.07 x 10^4 J ( as it decreases)

(c) According to the first law of thermodynamics  

Q = W + U

Q = 1.82 x 10^4 - 4.07 x 10^4

Q = - 2.25 x 10^4 J

4 0
3 years ago
Other questions:
  • Isotopes of uranium have the same number of ________ but a different number of _________.
    14·2 answers
  • 100Gw x 35ms (note: a watt is a joule per second)
    15·1 answer
  • It is known that a certain kind of algae in the Dead Sea can double in population every 2 days. Suppose that the population of a
    14·1 answer
  • Use the worked example above to help you solve this problem. An Alaskan rescue plane drops a package of emergency rations to str
    6·1 answer
  • What happens when the objects submerged in a fluid at rest?​
    14·1 answer
  • 3. Which of the following is the correctly abbreviated SI unit describing the mass of an object?
    6·1 answer
  • Settlers are trying to determine the value of g on a distant planet. They throw a wrench downward from a height of 3 m. If the i
    8·1 answer
  • Please help :/ The same motor is used in rockets with different masses. The rockets have different accelerations. According to N
    12·1 answer
  • Find the resultant force And angle
    11·1 answer
  • this is a 3 part questionOn vacation, your 1400-kg car pulls a 560-kg trailer away from a stoplight with an acceleration of 1.85
    12·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!