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Trava [24]
2 years ago
6

A submarine completed a 450 km training with an average speed of 50 km/h. For the first 180 km, it travelled at an average speed

of 60 km/h. What was the average speed for the remaining distance? Km/h
Physics
1 answer:
Kryger [21]2 years ago
4 0

Answer:

45km/hr

Explanation:

Total distance=450km

Total speed=50km/hr

Total time= distance/speed

=450/50

=9hrs

distance a=180km

speed a=60km/hr

Time a=180/60

=3hrs

Distance b=450-180=270km

Speed b=?

Time b=270/speed b

Total time=time a + time b

9=3+(270/speed b)

270/speed b =9-3

270/speed b =6

6*speed b =270

Speed b=270/6

Speed b=45km/hr

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Carts A and B are identical and are moving toward each other on a track. The speed of cart A is v, while the speed of cart B is
borishaifa [10]

Answer: k= \frac{5mv^{2} }{2}

Explanation:

Recall that the formula for kinetic energy is given below as

k = \frac{mv^{2} }{2}

where k=kinetic energy (joules), m= mass of object (kg), v= velocity of object m/s)

For cart A

m_{a} = mass of cart A

v_{a} = v = velocity of cart A

K.E_{a} = kinetic energy of cart A

hence, K.E_{a} = \frac{m_{a}v^{2}  }{2}

For cart B

m_{b} = mass of cart B

v_{b} = 2v = velocity of cart B

K.E_{b} = kinetic energy of cart B

hence, K.E_{b} = \frac{m_{b}(2v^{2}) }{2} = 2m_{b} v^{2}

from the question, both cart are identical which implies they have the same mass i.e m_{a} = m_{b} = m which implies that

K.E_{a}= \frac{mv^{2} }{2} and K.E_{b}  =2mv^{2}

The total kinetic energy K is the sum of cart A and cart B kinetic energy

K=K.E_{a} + K.E_{b}

K=\frac{mv^{2} }{2} + 2mv^{2}

hence

K=\frac{5mv^{2} }{2}

6 0
2 years ago
Which statement would be a valid argument in favor of using nuclear power? There are few negative impacts from mining the fuel.
fgiga [73]
Okay so, lets use the process of elimination here. 

<span>A)There are few negative impacts from mining the fuel.
B)Reactors are safe from natural disasters.
C)There are little to no waste products from fission.
D)Nuclear power does not contribute greenhouse gases.

First off, we know B cannot be correct, seeing as how reactors are fragile and are damaged easily by Japan's earthquakes. So we can eliminate B from the choices. We then can eliminate C, since fission creates high levels of nuclear waste, so that leaves us with just A, and D. We can then eliminate A since uranium is radioactive, there is always a chance for negative effects.

So, the correct answer is D</span>
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2 years ago
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ivanzaharov [21]
D. Teach the public energy conservation
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jasenka [17]

Answer:

Daria probably suffers from Entomophobia.

5 0
2 years ago
Which best describes nuclear fusion?
MrMuchimi

Answer:

The statement that best describes nuclear fusion is;

Nuclei combine to form a heavier nucleus, releasing energy

Explanation:

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Some nuclear fusion reaction require an input of energy and such reactions are therefore not spontaneous

The best option is nuclei (two or more nuclei) combine to form a heavier nucleus, releasing energy.

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