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Allushta [10]
2 years ago
13

Calculate the speed of an object which Travels 30 km distance in 4 hours​

Physics
1 answer:
nexus9112 [7]2 years ago
7 0

Answer:

The object is traveling 7.5 km per hour.

Explanation:

30/4 = 7.5

To check do 7.5 * 4 and you get 30

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For the following elementary reaction 2br• -> br2-. The rate of consumption of the reaction and the rate of formation of prod
Scorpion4ik [409]

Answer: -\frac{1}{2}\times \frac{d[Br^.]}{dt}=+\frac{d[Br_2]}{dt}

Explanation:

Rate of a reaction is defined as the rate of change of concentration per unit time.

Thus for reaction:

2Br^.\rightarrow Br_2

The rate in terms of reactants is given as negative as the concentration of reactants is decreasing with time whereas the rate in terms of products is given as positive as the concentration of products is increasing with time.

Rate=-\frac{d[Br^.]}{2dt}

or Rate=+\frac{d[Br_2]}{dt}

Thus -\frac{d[Br^.]}{2dt}=+\frac{d[Br_2]}{dt}

4 0
3 years ago
The earth has a vertical electric field at the surface, pointing down, that averages 100 N/C. This field is maintained by variou
zlopas [31]

Answer:

q = 3.6 10⁵  C

Explanation:

To solve this exercise, let's use one of the consequences of Gauss's law, that all the charge on a body can be considered at its center, therefore we calculate the electric field on the surface of a sphere with the radius of the Earth

          r = 6 , 37 106 m

          E = k q / r²

          q = E r² / k

          q = \frac{100 \ (6.37 \ 10^6)^2}{9 \ 10^9}

          q = 4.5 10⁵ C

Now let's calculate the charge on the planet with E = 222 N / c and radius

           r = 0.6 r_ Earth

           r = 0.6 6.37 10⁶ = 3.822 10⁶ m

           E = k q / r²

            q = E r² / k

            q = \frac{222 (3.822 \ 10^6)^2}{ 9 \ 10^9}

            q = 3.6 10⁵  C

4 0
3 years ago
Energy that cannot be used to do useful work is referred to as Select one: a. potential energy. b. entropy. c. kinetic energy. d
topjm [15]

In thermodynamics, entropy (symbolized as S) is a physical magnitude for a thermodynamic system in equilibrium. It measures the number of microstates compatible with the equilibrium macrostate, it can also be said that it is the reason for an increase between internal energy versus an increase in system temperature.

The universe tends to distribute energy evenly; that is, to maximize entropy. Intuitively, entropy is a physical quantity that, by calculation, allows us to determine the part of energy per unit of temperature that cannot be used to produce work.

Therefore the correct answer is B.

5 0
3 years ago
A 12.0 cm object is 9.0 cm from a convex mirror that has a focal length of -4.5 cm. What is the distance of the image from the m
Rasek [7]

Answer:

- 3 cm

Explanation:

From the mirror formula;

1/f = 1/v + 1/u ; where f is the focal length, v is the image distance, and u is the object distance.

1/-4.5 = 1/9 + 1/v

1/v = -1/4.5 - 1/9

    = -1/3

Therefore;

v = -3 cm

Hence;

Image distance is - 3cm

5 0
3 years ago
A 113 kg man sits on the stern of a 6.3 m long boat. The prow of the
Usimov [2.4K]

Answer:

m = 105.37 kg

Explanation:

We are given;

Mass of man; m = 113 kg

Length of boat = 6.3m

Now, The position of the center of mass will not change during the motion of the man.

Thus,

X_g,i = X_g,f

So,

[113(6.3) + ma]/(113 + m) = [113(3.26) + m(a +3.26)]/(113 + m)

113 + m will cancel on both sides to give;

113(6.3) + ma = [113(3.26) + m(a +3.26)]

711.9 + ma = 368.38 + ma + 3.26m

ma will cancel out to give;

711.9 - 368.38 = 3.26m

343.52/3.26 = m

m = 105.37 kg

3 0
3 years ago
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