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MaRussiya [10]
3 years ago
6

A man holds a child on his shoulders while watching a football match. How many work has he done if the game lasts for 2 hours? ​

Physics
2 answers:
Sedaia [141]3 years ago
8 0
Answer: ZERO!

work= F•d = F*d*cos(theta)

Since there is no displacement taking place then there is NO WORK being done! Cheers!
Shalnov [3]3 years ago
4 0

very interesting and amazing question u had asked but i get it...

Answer

  • work done is given by

W = Force × Displacement

  • but in above case force is exerted on the men as the weight of the child × gravitational pull of earth (9.8 m/s^2) but the displacement or movement is ZERO
  • there for W= F×0 =0
  • so even after carrying child for 2 hours work done by the men will be zero

<u>More</u><u> </u><u>examples</u>

  • a person standing straight and lifting weight
  • a person carry some weight and walk in a circular path and came back to its original position.........in this case also Displacement will be zero

------------------------------------

hope it helped u buddy

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The combined-gas law relates which of these?
Fofino [41]
The combined-gas law relates which temperature, pressure and volume.

Temperature=T
Pressure=P
Volume=V

(P₁*V₁) / T₁=(P₂*V₂) / T₂

D. Temperature, pressuere and volume.
5 0
3 years ago
Singly charged uranium-238 ions are accelerated through a potential difference of 2.90 kV and enter a uniform magnetic field of
Lera25 [3.4K]

Answer: 0.091 m

Explanation:

r = 1/B * √(2mV/e), where

r = radius of their circular path

B = magnitude of magnetic field = 1.29 T

m = mass of Uranium -238 ion = 238 * amu = 238 * 1.6*10^-27 kg

V = potential difference = 2.9 kV

e = charge of the Uranium -238 ion = 1.6*10^-19 C

r = 1/1.29 * √[(2 * 238 * 1.6*10^-27 * 2900) / 1.6*10^-19]

r = 1/1.29 * √(2.21*10^-21 / 1.6*10^-19)

r = 1/1.29 * √0.0138

r = 1/1.29 * 0.117

r = 0.091 m

Therefore, the radius of their circular path is 0.091 m

6 0
3 years ago
Suppose a rectangular piece of aluminum has a length D, and its square cross section has the dimensions W XW, where D (W x W) to
Ludmilka [50]

Answer:

R₂ / R₁ = D / L

Explanation:

The resistance of a metal is

        R = ρ L / A

Where ρ is the resistivity of aluminum, L is the length of the resistance and A its cross section

We apply this formal to both configurations

Small face measurements (W W)

The length is

         L = W

Area  

         A = W W = W²

        R₁ = ρ W / W² = ρ / W

Large face measurements (D L)

       Length L = D= 2W

       Area     A = W L

     R₂ = ρ D / WL = ρ 2W / W L = 2 ρ/L

The relationship is

    R₂ / R₁ = 2W²/L

6 0
3 years ago
what is the ratio of ey,final, the maximum value of the y-component of the electric field immediately following the last polariz
OleMash [197]

That ratio is 2 .

<h3>What is ratio?</h3>

A ratio is the  comparison of the  two numbers bydivision.

Taking the first two outputs, or the  -1/8 and -1/4, we can divide not the second one by the first one to find the

ratio:

-1/4-1/8

When dividing fractions, we multiply by the reciprocal:

-1/4x-8/1

To multiply fractions, multiply straight across:

(-1x-8)/(4x1) 8/4=2

To know more about ratio click-

brainly.com/question/25927869

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8 0
1 year ago
You are doing an experiment to determine your reaction time. Your friend holds a ruler. You place your fingers near the sides of
olga2289 [7]
I'm guessing that you mean like this:
-- The ruler is held with zero at the bottom, and the centimeter markings
    increase as you go up the ruler.
-- You place your fingers with the ruler and the zero mark between them.
-- The number where you catch the ruler is the distance it has fallen.

Then, all we have to find is the time it takes for the ruler to fall 11.3 cm .

Here's the formula for the distance an object falls from rest
in a certain time:

                Distance = (1/2) (gravity) (time)²

On Earth, the acceleration of gravity is 9.8 m/s².
So we can write ...

                              11.2 cm  =  (1/2) (9.8 m/s²) (time)²
or
                         0.112 meter  =  (4.9 m/s²) (time)²                      

Divide each side
by  4.9 m/s² :        (0.112 m) / (4.9 m/s²)  =  time²

                            (0.112 / 4.9)  sec²  =  time²

Square root
each side:            time = √(0.112/4.9  sec²)

                                  =  √ 0.5488 sec²

                                  =      0.74 second     (rounded)  

4 0
3 years ago
Read 2 more answers
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