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beks73 [17]
3 years ago
9

A blue train of mass 50 kg moves at 4 m/s toward a green train of 30 kg initially at rest. What is the initial momentum of the g

reen train?
Physics
1 answer:
soldi70 [24.7K]3 years ago
6 0

Answer:

I think answer is zero

bcz momentum=mass×velocity

body was initially at rest it means its velocity is zero

30×0=0

You might be interested in
A heat engine has a maximum possible efficiency of 0.780. If it operates between a deep lake with a constant temperature of-24.8
Volgvan

Answer : The temperature of the hot reservoir (in Kelvins) is 1128.18 K

Explanation :

Efficiency of carnot heat engine : It is the ratio of work done by the system to the system to the amount of heat transferred to the system at the higher temperature.

Formula used for efficiency of the heat engine.

\eta =1-\frac{T_c}{T_h}

where,

\eta = efficiency = 0.780

T_h = Temperature of hot reservoir = ?

T_c = Temperature of cold reservoir = -24.8^oC=273+(-24.8)=248.2K

Now put all the given values in the above expression, we get:

\eta =1-\frac{T_c}{T_h}

0.780=1-\frac{248.2K}{T_h}

T_h=1128.18K

Therefore, the temperature of the hot reservoir (in Kelvins) is 1128.18 K

8 0
3 years ago
Calculate (a) the torque, (b) the energy, and (c) the average power required to accelerate Earth in 4.0 days from rest to its pr
natima [27]
<h2>Answer:</h2>

Torque = <em>2.05 x 10²⁸ Nm</em>

Energy = <em>3.54 x 10³³ J</em>

Average power = <em>1.02 x 10²⁸ W</em>

<h2>Explanation:</h2>

(a) Torque (τ) is the rotational effect of a given force.  

It is given by

τ = I x α          -------------(i)

Where;

I = rotational inertia of the object

α = angular acceleration of the object.

In this case, the object is the Earth. Therefore,

I = 9.71 x 10³⁷ kg m²

α = ω / t

Where;

ω = angular velocity of earth = 2π rad / day

<em>Since </em>

<em>1 day = 24 hours and 1 hour = 3600seconds</em>

<em>1 day = 24 x 3600 seconds = 86400seconds</em>

<em>=> ω = 2π rad / 86400seconds</em>

<em>=> ω = 7.29 × 10⁻⁵ rad/s</em>

<em />

t = 4 days = 4 x 24 x 3600 seconds = 345600 seconds

=> α = ω / t

=> α = 7.29 × 10⁻⁵ / 345600

=> α = (7.29 × 10⁻⁵) / (3.456 x 10⁵)

=> α = (7.29 × 10⁻⁵⁻⁵) / (3.456)

=> α = (7.29 × 10⁻¹⁰) / (3.456)

=> α = 2.11 × 10⁻¹⁰ rad/s²

Now substitute the values of I and α into equation (i)

τ = 9.71 x 10³⁷ x 2.11 × 10⁻¹⁰

τ = 9.71 x 10²⁷ x 2.11

τ = 20.5 x 10²⁷ Nm

τ = 2.05 x 10²⁸ Nm

(ii) The energy (rotational energy) E is given by;

E = \frac{1}{2} x I x ω

E = \frac{1}{2} x 9.71 x 10³⁷ x 7.29 × 10⁻⁵

E = 35.4 x 10³² J

E = 3.54 x 10³³ J

(iii) The average power P, is given by;

P = E / t

P = 3.54 x 10³³ / 345600

P = 1.02 x 10²⁸ W

5 0
3 years ago
Minority group
Margarita [4]

Answer:

Minority group - People who are singled  out for unequal treatment  and who regard  themselves as objects of  collective discrimination.

Ethnicity - A shared identity based on  cultural elements such as  heritage, language, and  religion.

Majority group - A group's subset that  consists of more than half  of the entire group's  members.

Race - A socially constructed  group of people who share  physical characteristics  that are considered  significant by a society  and that are used to  distinguish them from  other groups.

Explanation:

To better understand the above-mentioned definitions we would use some examples:

Elder people can be considered as a minority group in the United States because of their reduced status as a consequence of popular discrimination and prejudice against them. In contrast to them, young men consisting of more than half the population in the age category is an example of the majority group.

Groups of people like Hispanic Americans, Jews, Italian America, Irish are some examples of people belonging to different ethnic backgrounds residing in the U.S.

African Americans who are distinguished based on their skin color is an example of race.

6 0
3 years ago
What is the unit of velocity ratio and mechanical advantage and why​
alexandr402 [8]
Both don’t have units beacuse they are ratios
8 0
3 years ago
If a wave has amplitude of 2 meters, a wavelength of 2 meters, and a frequency of 10 Hz, and a period of 1 second, then at what
Serhud [2]

Answer:

20 m/s

Explanation:

The speed of a wave is given by:

v=\lambda f

where

\lambda is the wavelength

f is the frequency

v is the speed

For the wave in this problem,

f = 10 Hz is the frequency

\lambda=2 m is the wavelength

So the speed is

v=(10 Hz)(2 m)=20 m/s

6 0
2 years ago
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