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LenKa [72]
3 years ago
13

An escalator is 18.3 m long. If a person stands on the escalator, it takes 47.8 s to ride from the bottom to the top. If a perso

n walks up the moving escalator with a speed of 0.521 m/s relative to the escalator, how long does it take the person to get to the top?
Physics
1 answer:
Novay_Z [31]3 years ago
8 0

Answer:

20.243 s

Explanation:

Because the escalator and person moving in the same direction, relative velocity can be calculated by summing the velocity of the escalator and velocity of the person.  

The speed of escalator can be calculated as,

v_{escalator}=\frac{x}{t}=\frac{18.3}{47.8}=0.383\ m/s

Relative velocity

v_{relative}=v_{escalator}+v_{person}\\\\v_{relative}=0.383+0.521=0.904\ m/s\\

Therefore total time required to take the person to get to the top

t=\frac{x}{v_{relative}}= \frac{18.3}{0.904}=20.243\ s

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Paha777 [63]

Answer:

15.75 m

Explanation:

First, let's look at the top brick by itself.  In order for it not to tip over the bottom brick, its center of gravity must be right at the edge of the bottom brick.  So the edge of the top brick must be 10.5 m from the edge of the bottom brick.

Now let's look at both bricks as a combined mass.  We know the total length of this combined brick is 10.5 m + 21 m = 31.5 m.  And we know that for it to not tip over the edge of the surface, its center of gravity must be at the edge.  So the edge of the combined brick must be 31.5 m / 2 = 15.75 m from the edge of the surface.

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3 years ago
A mass m attached to a spring of constant k is oscillating on a frictionless surface. A second mass of mass m is dropped on top
elixir [45]

Answer:

E. The period of oscillation increases.

Explanation:

The period of oscillation is:

T = 2π√(m/k)

Frequency is the inverse of period (f = 1/T), so as period increases, frequency decreases.

Increasing the mass will increase the period and decrease the frequency.

8 0
2 years ago
Two round concentric metal wires lie on a tabletop, one inside the other. The inner wire has a diameter of 21.0 cm and carries a
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Solution :

a). B at the center :

     $=\frac{u\times I}{2R}$

Here, one of the current is in the clockwise direction and therefore, the other current must be in the clockwise direction in order to cancel out the effect of the magnetic field that is produced by the other.

Therefore, the answer is ANTICLOCKWISE or COUNTERCLOCKWISE

b). Also, the sum of the fields must be zero.

Therefore,

$\left(\frac{u\times I_1}{2R_1}\right) + \left(\frac{u\times I_2}{2R_2}\right) = 0$

So,

$\frac{I_1}{d_1}= \frac{I_2}{d_2}$

$=\frac{16}{21}=\frac{I_2}{32}$

$I_2=24.38 $ A

Therefore, the current in the outer wire is 24.38 ampere.

3 0
2 years ago
Read 2 more answers
A copper block rests 30.0 cm from the center of a steel turntable. The coefficient of static friction between the block and the
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Answer:

refer to the above attachment

3 0
1 year ago
According to Kepler's Second Law the radius vector drawn from the Sun to a planet Multiple Choice is the same for all planets. s
Mademuasel [1]

Answer:

sweeps out equal areas in equal times.

Explanation:

As we know that there is no torque due to Sun on the planets revolving about the sun

so we will have

\tau_{net} = 0

now we have

\frac{dL}{dt}= 0

now we also know that

Area = \frac{1}{2}r^2d\theta

so rate of change in area is given as

\frac{dA}{dt} = \frac{1}{2}r^2\frac{d\theta}{dt}

so we will have

\frac{dA}{dt} = \frac{1}{2}r^2\omega

\frac{dA}{dt} = \frac{L}{2m}

since angular momentum and mass is constant here so

all planets sweeps out equal areas in equal times.

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3 years ago
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