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posledela
3 years ago
14

Which of the following situations describes static friction? a. A heavy crate standing on a rough patch of mud and is being push

ed by two workers, but they cannot get it to move b. A large piano resting on a sheet of ice is being pushed by a child, but the child is not strong enough to get it to move
Physics
2 answers:
marin [14]3 years ago
8 0

Answer:

A.

Explanation:

The answer is A because the weight of the crate is sitting on something rough. The roughness is going to resist anything that tries to move against it because the force being exerted by the 2 workers is not strong enough to get the crate to move out of its place on the mud since it's static.

The answer can't be B because ice is smooth and doesn't have any friction, the little girl can't move it because it's to heavy for her to move, not because there's friction acting against it.

Yuliya22 [10]3 years ago
3 0

Answer:

A. A heavy crate standing on a rough patch of mud and is being pushed by two workers, but they cannot get it to move.

Explanation:

I got it correct on the test.

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A 66​-foot-tall woman walks at 55 ​ft/s toward a street light that is 2424 ft above the ground. What is the rate of change of th
I am Lyosha [343]

Answer:

a. \frac{dx}{dt}=20ft/s

b. \frac{d(x+L)}{dt}==25ft/s

Explanation:

Using the triangle theorem both triangle the woman makes between the light so the rate of change of length can use geometry first

tan(\beta)=\frac{24ft}{L+x}=\frac{6ft}{x}

Solve to find the rate relation

x=\frac{24}{6}*L

x=4*L

Now the rate of the change rate

\frac{dx}{dt}=4*\frac{dL}{dt}

\frac{dx}{dt}=4*5ft/s=20ft/s

Finally the rate of her shadow moving

\frac{d(x+L)}{dt}=\frac{dx}{dt}+\frac{dL}{dt}

\frac{d(x+L)}{dt}=20ft/s+5ft/s=25ft/s

5 0
3 years ago
The early workers in spectroscopy (Fraunhofer with the solar spectrum, Bunsen and Kirchhoff with laboratory spectra) discovered
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The hot gases produce their own characteristic pattern of spectral lines, which remain fixed as the temperature increases moderately.

<h3><u>Explanation: </u></h3>

A continuous light spectrum emitted by excited atoms of a hot gas with dark spaces in between due to scattered light of specific wavelengths is termed as an atomic spectrum. A hot gas has excited electrons and produces an emission spectrum; the scattered light forming dark bands are called spectral lines.

Fraunhofer closely observed sunlight by expanding the spectrum and a huge number of dark spectral lines were seen.  "Robert Bunsen and Gustav Kirchhoff" discovered that when certain chemicals were burnt using a Bunsen burner, atomic spectra with spectral lines were seen. Atomic spectral pattern is thus a unique characteristic of any gas and can be used to independently identify presence of elements.

The spectrum change does not depend greatly on increasing temperatures and hence no significant change is observed in the emitted spectrum with moderate increase in temperature.

8 0
3 years ago
A 132 cm wire carries a current of 2.2 A. The wire is formed into a circular coil and placed in a B Field of intensity 1 T. a) F
EastWind [94]

Given Information:

Length of wire = 132 cm = 1.32 m

Magnetic field = B =  1 T

Current = 2.2 A

Required Information:

(a) Torque = τ = ?

(b) Number of turns = N = ?

Answer:

(a) Torque = 0.305 N.m

(b) Number of turns = 1

Explanation:

(a) The current carrying circular loop of wire will experience a torque given by

τ = NIABsin(θ)   eq. 1

Where N is the number of turns, I is the current in circular loop, A is the area of circular loop, B is the magnetic field and θ is angle between B and circular loop.

We know that area of circular loop is given by

A = πr²

where radius can be written as

r = L/2πN

So the area becomes

A = π(L/2πN)²

A = πL²/4π²N²

A = L²/4πN²

Substitute A into eq. 1

τ = NI(L²/4πN²)Bsin(θ)

τ = IL²Bsin(θ)/4πN

The maximum toque occurs when θ is 90°

τ = IL²Bsin(90)/4πN

τ = IL²B/4πN

torque will be maximum for N = 1

τ = (2.2*1.32²*1)/4π*1

τ = 0.305 N.m

(b) The required number of turns for maximum torque is

N = IL²B/4πτ

N = 2.2*1.32²*1)/4π*0.305

N = 1 turn

8 0
3 years ago
A 2100-kg pile driver is used to drive a steel I-beam into the ground. The pile driver falls 5.00 m before coming into contact w
aliya0001 [1]

Answer:

   f = 878,080 N

Explanation:

mass of pile driver (m) = 2100 kg

distance of pile driver to steel beam (s) = 5 m

depth of steel driven (d) = 12 cm = 0.12 m

acceleration due to gravity (g0 = 9.8 m/s^{2}

calculate the average force exerted on the pile driver by the beam.

  • from work done = force x distance
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               force x distance = m x g x (s - d)

              f x 0.12 = 2100 x 9.8 x (5- (-0.12))

              d = - 0.12 because the steel beam went down at we are taking its  

              initial position to be an origin point which is 0

              f = ( 2100 x 9.8 x (5- (-0.12)) ) ÷ 0.12

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4 0
3 years ago
According to the law of conservation of momentum, objects will either stick together or bounce off of each other when they colli
Tanzania [10]
F - False.

The law of conservation of momentum states that the total momentum is conserved.
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3 years ago
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