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saul85 [17]
4 years ago
13

A rocket passes you at a speed of 0.85c, and you measure its length to be 35.0 m. What is its measured length when at rest?

Physics
1 answer:
viktelen [127]4 years ago
8 0

Answer:

66.4 m

Explanation:

To solve the problem, we can use the length contraction formula, which states that the length observed in the reference frame moving with the object (the rocket) is given by

L=L_0 \sqrt{1-(\frac{v}{c})^2}

where

L_0 is the proper length (the length measured from an observer at rest)

v is the speed of the object (the rocket)

c is the speed of light

Here we know

v = 0.85c

L = 35.0 m

So we can re-arrange the equation to find the length of the rocket at rest:

L_0 = \frac{L}{\sqrt{1-(\frac{v}{c})^2}}=\frac{35.0}{\sqrt{1-(\frac{0.85c}{c})^2}}=66.4 m

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Water at 20°C flows by gravity through a smooth pipe from one reservoir to a lower one. The elevation difference is 60 m. The pi
Serga [27]

Answer:

Flow Rate = 80 m^3 /hours  (Rounded to the nearest whole number)

Explanation:

Given

  • Hf = head loss
  • f = friction factor
  • L = Length of the pipe = 360 m
  • V = Flow velocity, m/s
  • D = Pipe diameter = 0.12 m
  • g = Gravitational acceleration, m/s^2
  • Re = Reynolds's Number
  • rho = Density =998 kg/m^3
  • μ = Viscosity = 0.001 kg/m-s
  • Z = Elevation Difference = 60 m

Calculations

Moody friction loss in the pipe = Hf = (f*L*V^2)/(2*D*g)

The energy equation for this system will be,

Hp = Z + Hf

The other three equations to solve the above equations are:

Re = (rho*V*D)/ μ

Flow Rate, Q = V*(pi/4)*D^2

Power = 15000 W = rho*g*Q*Hp

1/f^0.5 = 2*log ((Re*f^0.5)/2.51)

We can iterate the 5 equations to find f and solve them to find the values of:

Re = 235000

f = 0.015

V = 1.97 m/s

And use them to find the flow rate,

Q = V*(pi/4)*D^2

Q = (1.97)*(pi/4)*(0.12)^2 = 0.022 m^3/s = 80 m^3 /hours

7 0
3 years ago
A person is drinking a glass of soda with ice.
prisoha [69]

The relative kinetic energy of molecules in the soda is least energy and above the soda in the glass is greatest energy.

The relative kinetic energy of gas molecules increases with increase in the mean distance between the gas molecules.

Also, relative kinetic energy of gas molecules increases with in the temperature of the gas molecules and decreases with a decrease in the temperature of the of the gas molecules;

ΔK.E ∝ T

The ice in the soda lowers the temperature of the gas molecules, thereby reducing their average speed which in turn reduces the average kinetic energy of the gas molecules in the soda.

Above the soda in the glass, the concentration of the gas molecules is less and their mean distance is greatest when compared to inside the soda. This results to an increase in the speed of the gas molecules which increases their average kinetic energy.

Thus,  the relative kinetic energy of molecules in the soda is least energy and above the soda in the glass is greatest energy.

Learn more about temperature and kinetic energy here: brainly.com/question/305606

3 0
3 years ago
U guys are the best I’m surprised I’m getting all of this right
ella [17]
The answer is B, 1/4 of the cake
5 0
3 years ago
Read 2 more answers
The distance between Earth and Mars is 225 million km. When converted using the conversion factor 1 AU = 1.5 × 108 km, the dista
SIZIF [17.4K]
I guess the problem is asking for the distance between Earth and Mars in Astronomical Units (AU).

Since 1 AU = 1.5 \cdot 10^8 km
and the distance between the two planets is
d=225 mil. km= 2.25 \cdot 10^8 km
we can convert this distance into AU by using the following proportion:
1 AU : 1.5 \cdot 10^8 km = x : 2.25 \cdot 10^8 km

from which we find
x= \frac{1 AU \cdot 2.25 \cdot 10^8 km}{1.5 \cdot 10^8 km} =1.5 AU
7 0
3 years ago
Read 2 more answers
A powerful motorcycle can accelerate from rest to 24.8 m/s (55 mi/h) in only 5.90 s. (a) What is its average acceleration in m/s
mel-nik [20]

Answer

given,

initial speed,u = 0 m/s

final speed,v = 24.8 m/s

time, t= 5.9 s

a) acceleration,

a=\dfrac{v-u}{t}

a=\dfrac{24.8 - 0}{5.9}

     a = 4.20 m/s²

b) distance to travel in that time

using equation of motion

   v² = u² + 2 as

   24.8² = 0² + 2 x 4.20 x s

       8.4 s = 615.04

          s = 73.22 m

the motorcycle will travel 73.22 m

6 0
4 years ago
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