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
olganol [36]
3 years ago
12

A string is wrapped around a disk of mass 1.7 kg and radius 0.11 m. Starting from rest, you pull the string with a constant forc

e 7 N along a nearly frictionless surface. At the instant when the center of the disk has moved a distance 0.15 m, your hand has moved a distance of 0.22 m.
a. At this instant, what is the speed of the center of mass of the disk?
b. At this instant, how much rotational kinetic energy does the disk have relative to its center of mass?
Physics
2 answers:
V125BC [204]3 years ago
5 0

Answer:

Explanation:

a) work done in moving the disk by 0.15 m = its kinetic energy = 0.5 mv²

Fd = 0.5 mv²

2 fd = mv²

√( \frac{2fd}{m}) = v

v = 1.11 m/s

b) rotational kinetic energy = F ( 0.22 m - 0.15 m) = 0.49 J

Evgen [1.6K]3 years ago
5 0

Answer:

(a) Vcm = 1.43m/s

(b) KEcm = 2.59J

Explanation:

Given

m = mass of the solid disk = 1.7kg

Radius R = 0.11m

F = 7N

Let the distance moved by the the center of mass be x = 0.15m

And the distance moved by in unwinding the rope be d = 0.22m

The total workdone on the disk is causing it to rotate and also move its center of mass is F×(d+x)

W = 7×(0.15+0.22)

= 7× 0.37 = 2.59J

By work-energy theorem,

W = ΔKE = 1/2mVcm² + 1/2×I×ω²....(1)

I = moment of inertia = 1/2MR² and

ω = angular speed = Vcm/R

So substituting these expressions into the equation above we have

W = 1/2MVcm² + 1/2×1/2MR²×(Vcm/R)²

W = 1/2MVcm² + 1/4MVcm²

W = 3/4MVcm²

Vcm² = 4/3×W/M

Vcm = √(4/3×W/M)

Vcm = √(4/3×2.59/1.7)

Vcm = 1.43m/s

KE = workdone = 2.59J.

You might be interested in
A car is traveling at 39.7 mi/h on a horizontal highway. The acceleration of gravity is 9.8 m/s 2 . If the coefficient of fricti
777dan777 [17]

Answer:

The minimum distance in which the car will stop is

x=167.38m

Explanation:

39.7\frac{mi}{h}*\frac{1km}{0.621371mi}*\frac{1000m}{1km}*\frac{1h}{3600s}=17.747\frac{m}{s}

∑F=m*a

∑F=u*m*g

The force of friction is the same value but in different direction of the force moving the car so it can stop so

F=m*a\\a=\frac{F}{m}\\a=\frac{u*m*g}{m}\\a=u*g\\a=0.096*-9.8\frac{m}{s^{2} }

a=-0.9408 \frac{m}{s^{2}}

v_{f}^{2}=v_{o}^{2}+2*a*(x_{f}-x_{o})\\v_{f}=0 \\x_{o}=0\\0=v_{o}^{2}+2*a*x_{f}\\x_{f}=\frac{v_{o}^{2}}{2*a} \\x_{f}=\frac{(-17.747\frac{m}{s})^{2}}{2*(-0.9408)} \\x_{f}=167.38m

4 0
3 years ago
Relationship between voltage, resistance and current in a circuit
Lena [83]

Answer:

V = I×R

where -

V = potential difference across

I = current flowing in the circuit

R = Equivalent Resistance in the circuit

8 0
2 years ago
Why were the rings of Uranus not observed directly from telescopes on the ground on Earth? How were they discovered?
leonid [27]

Answer:Explained below.

Explanation:

Uranus rings is made up of jet black, coal-like particles in small bands, making them difficult  to perceive from Earth.This indicates that they are probably composed of a mixture of the ice and a dark material. The nature of  material is dismal, but it might be some organic compounds greatly darkened by the charged particle irradiation from the Uranian magnetosphere. Rings were discovered by using a infrared telescope throughout  the occultation of a star as Uranus passed in front of it. The light from the star dimmed many times before it was obstructed by the disk of Uranus and subsequently, showing the presence of various distinct rings.

6 0
3 years ago
Find the angle ϕ between the filter's polarizing axis and the direction of polarization of light necessary to increase the ratio
nika2105 [10]
D. that looks like a rubber band.
3 0
3 years ago
1. What happens when like charges come together?*
12345 [234]

Answer:

When like charges come together, they repel each other. For instance, when the north and south poles of a magnet come together, they push each other apart. The like poles in the magnet repel each other and unlike poles attract each other much. The same reaction occurs in like and unlike charges. Also, the repulsion acts along the line between the two charges.

4 0
3 years ago
Other questions:
  • Assume that the wavelengths of photosynthetically active radiations (PAR) are uniformly distributed at integer nanometers in the
    10·1 answer
  • Help!! I’ll give brainliest! Match the changes in sound wave properties with their effects on an observer.
    6·1 answer
  • Notice that in each conversion factor the numerator equals the denominator when units are taken into account. A common error in
    8·1 answer
  • The boom is supported by the winch cable that has a diameter of 0.5 in. and allowable normal stress of σallow=21 ksi. A boom ris
    6·1 answer
  • Explain how a Faraday motor works, please. Help me out
    5·1 answer
  • Select True or False for the following statements about conductors in electrostatic equilibrium. All points of a conductor are a
    5·1 answer
  • A small rubber ball is launched by a compressed-air cannon from ground level with an initial speed of 17.3 m/s directly upward.
    15·1 answer
  • How does a compass needle respond when a compass is placed within a magnetic field? It aligns in a direction parallel to the fie
    11·2 answers
  • Please help it’s urgent!
    5·1 answer
  • What type of wave carry sound energy forward?
    13·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!