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Damm [24]
2 years ago
15

A car travels a distance of 140 km at 70.0 km/hr. It then travels an additional distance of 60.0 km at 40.0 km/hr. The average s

peed is
Physics
1 answer:
Natali5045456 [20]2 years ago
5 0

Answer:

57.1 km/hr

Explanation:

To find the average speed you take the total distance divided by the total elapsed time.

So, the total distance is 140 + 60 = 200

the total elapsed time is found by taking 140/70=2 and 60/40=1.5

2+1.5=3.5

The plug the numbers into the equation,

200/3.5=57.1

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In stars mor massive than the sun, fusion continues until the core is almost all....
serious [3.7K]
In stars more massive than the sun, the core temperature is hotter, which allows for fusion of more complex elements.

Most of the fusion occurs in the core.

In stars more massive than the sun, fusion continues through Deuterium, Carbon, and finally reaching iron/nickel.

Up to this point, the fusion reaction was endothermic, which means that the energy expended to produce the fusion reaction was exceeded by the energy produced in the reaction.

Fusion past iron is exothermic, and therefore the star will be able to survive by fusing elements heavier than iron.

After the core is almost entirely iron, the star is no longer in the Main Sequence.

So, fusion in stars more massive than the sun continue fusing until the core is almost entirely <em>iron</em>.
3 0
3 years ago
A force of 100 N acts on a body and moves at a distance of 2 m in the direction of the force. How much work has been done?
Flauer [41]

Answer:

200 joules

Explanation:

work=force×distance

5 0
2 years ago
Cesium-137 undergoes beta decay and has a half-life of 30.0 years. How many beta particles are emitted by a 14.0-g sample of ces
Mandarinka [93]

Answer: 0.81\times 10^{16} beta particles

Explanation:

\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}

Given mass = 14.0 g

Molar mass = 137 g/mol

\text{Number of moles of cesium}=\frac{14.0g}{137g/mol}=0.102moles

According to avogadro's law, 1 mole of every substance weighs equal to its molecular mass and contains avogadro's number 6.023\times 10^{23} of particles.

1 mole of cesium contains atoms =  6.023\times 10^{23}

0.102 moles of cesium contains atoms =  \frac{6.023\times 10^{23}}{1}\times 0.102=0.614\times 10^{23}

The relation of atoms with time for radioactivbe decay is:

N_t=N_0\times \frac{1}{2}^{\frac{t}{t_{\frac{1}{2}}}}

Where N_t =atoms left undecayed

N_0 = initial atoms

t = time taken for decay = 3 minutes

{t_{\frac{1}{2}}} = half life = 30.0 years = 1.577\times 10^7 minutes

The fraction that decays  :  1-(\frac{1}{2})^{\frac{3}{1.577\times 10^7}}=1.32\times 10^{-7}

Amount of particles that decay is  = 0.614\times 10^{23}\times 1.32\times 10^{-7}=0.81\times 10^{16}

Thus 0.81\times 10^{16} beta particles are emitted by a 14.0-g sample of cesium-137 in three minutes.

7 0
2 years ago
As Aubrey watches this merry-go-round for a total of 2 minutes, she notices the black horse pass by 15 times. What is the period
Hunter-Best [27]
Periodic time is the time taken for one complete oscillation by a body in circular motion. In this case the merry-go round takes 2 minutes to cover 15 complete oscillations. 2 Minutes = 120 seconds
Hence, 15 oscillations takes 120 secs
         thus 1 oscillation takes 120/15 = 8 seconds
therefore the period of the merry-go-round = 8 seconds
8 0
3 years ago
Read 2 more answers
What will occur when the waves peak at the same place at the same time?
dedylja [7]
Hello!

This is a matter of superposition.
When the waves peak at the same time and place, they produce constructive interference, meaning the waves interact together in a positive way, to make a wave with Amplitude of both waves added together. When the peaks differ however, at the same time and place, then it is destructive interference and the waves essentially cancel each other out.

Hope this helps. Any questions please just ask. Thank you kindly.
5 0
2 years ago
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