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
anyanavicka [17]
3 years ago
6

A man stands on a platform that is rotating at 3.8 rpm; his arms are outstretched and he holds a brick in each hand. The rotatio

nal inertia of the system consisting of the man, bricks, and platform about the central axis of the platform is 4.65 kg-m². By moving the bricks the man decreases the rotational inertia of the system to 3.4 kg-m².
(a) what is the resulting angular speed of the platform and
(b) what is the ratio of the new kinetic energy of the system to the original kinetic energy?

Physics
2 answers:
Ierofanga [76]3 years ago
8 0

Answer:

a) 5.197rev/s

b) Kf/Ki =2.28

Explanation:

a) Angular momentum of the system L = Iw

ButLi=Lf

Kiwi =Ifwf

wf = (Ii/If)will = (4.65/3.4)×3.8=5.197rev/s

b)Kinetic energy KE= 0.5Iw^2

Ki = 0.5Iiwi^2

Kf=0.5Ifwf^2

Kf/Ki = Ifwf/Iiwi

Kf/Ki = (4.65/3.4))(5.197/3.8)

Kf/Ki = 1.22(1.368)^2

Kf/Ki = 2.28

kiruha [24]3 years ago
7 0

Answer:

A. 5.2 rpm.

B. Kf/Ki = 1.37.

Explanation:

Below is an attachment containing the solution.

You might be interested in
g A change in the initial _____ of a projectile changes the range and maximum height of the projectile.​
docker41 [41]

Answer:

Velocity.

Explanation:

Projectile motion is characterized as the motion that an object undergoes when it is thrown into the air and it is only exposed to acceleration due to gravity.

As per the question, 'any change in the initial velocity of the projectile(object having gravity as the only force) would lead to a change in the range as well as the maximum height of the projectile.' To illustrate numerically:

Horizontal range: As per expression:

R= (u^{2}*sin2θ)/g

the range depending on the square of the initial velocity.

Maximum height: As per expression:

H= (u^{2} * sin^{2}θ )/2g

the maximum distance also depends upon square of the initial velocity.

​

​

​

7 0
3 years ago
Critical angle of glass is 42 .what does it mean?​
elena55 [62]

Answer:

i think..its fraction that its have multiple fractions on it..if you minus the 397 000-355 it should be 381+ so i say if you get the 5 multiply it by 9!! so you will get it!

Explanation:

HOPE IT HELPS!!

6 0
3 years ago
An object with a mass of 20 kg has a net force of 80 N acting on it. What is the acceleration of the object?
Archy [21]

Answer:

4m/s^2

Explanation:

mass(m)=20 kg

force=80 N

acceleration (a)=?

Therefore,

Force = mass * acceleration

80 = 20*a

a=80/20

=4m/s^2

7 0
2 years ago
if a torque of 55.0 N/m is required and the largest force that can be exerted by you is 135 N what is th e length of the lever a
Whitepunk [10]

Answer:

r=0.41m

Explanation:

Torque is defined as the cross product between the position vector ( the lever arm vector connecting the origin to the point of force application) and the force vector.

\tau=r\times F

Due to the definition of cross product, the magnitude of the torque is given by:

\tau=rFsin\theta

Where \theta is the angle between the force and lever arm vectors. So, the length of the lever arm (r) is minimun when sin\theta is equal to one, solving for r:

r=\frac{\tau}{F}\\r=\frac{55\frac{N}{m}}{135N}\\r=0.41m

7 0
3 years ago
The friction that prevents an object from moving when a force is applied is ________ friction.
uranmaximum [27]
Static friction is what you are looking for.
Kinetic friction is the force exerted on an already moving object, slowing it down.
3 0
3 years ago
Other questions:
  • Find the work w1 done on the block by the force of magnitude f1 = 65.0 n as the block moves from xi = -3.00 cm to xf = 3.00 cm .
    13·1 answer
  • The images that come to mind when we think of a place, any place, like Tucson, Arizona or Damascus, Syria are known as ourA) cog
    12·1 answer
  • Answer the following questions:
    14·2 answers
  • PLEASE HELP WILL GIVE BRAINLIEST!!!!!!!
    6·1 answer
  • Maxwell’s theory of Electromagnetism in 1865 was the first "unified field theory" _________ no further theory has united the ele
    14·1 answer
  • A 0.035 kg shooter marble with a velocity of 0.77 m/s. forward, hits a 5.2 x 10-³ kg marble that is at rest. The
    9·1 answer
  • I what is the resistance of
    6·1 answer
  • Write 3 major differences between a shadow and a image?
    9·2 answers
  • If a car skids to a stop in 3.8s while undergoing a uniform acceleration of -9.55 m/s2, what is the car’s velocity?
    6·1 answer
  • Write equations for both the electric and magnetic fields for an electromagnetic wave in the red part of the visible spectrum th
    8·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!