2 years ago

A train travels 225 kilometers in 2.5 hours. What is the train’s average speed?

2 answers:

7 0

The train travells at he speed of 225 km/2.5h
now
225km=225000m
2.5 hr=150min=9000s
=>avg sp of train is=225000/9000s=25m/s

satela [25.4K]2 years ago

7 0

Answer:

562.5

Explanation:

You might be interested in

ANOTHER PHYSICS QUESTION PLEASE HELP!

Sergio039 [100]

Answer

= 60

Hope it helps:)

5 0

2 years ago

What is the smallest part of a chemical compound that has all the properties

mel-nik [20]

Answer:

D. A Molecule

Explanation:

<em>The smallest particle of a compound that still has the properties of the compound is a molecule. It is composed of two or more bonded atoms.</em>

5 0

2 years ago

How much heat is required to warm 122 g of water by 23.0 c?

GaryK [48]

4 0

2 years ago

Read 2 more answers

The temperature of a solution will be estimated by taking n independent readings and averaging them. Each reading is unbiased, w

Viktor [21]

Answer:

68 readings.

Explanation:

We need to take this problem as a statistic problem where the normal distribution table help us.

We can start considerating that X is the temperature of the solution, then

$0.9 = P(|\bar{x}-\mu|$

$0.9 = P(\frac{|\bar{x}-\mu|}{\frac{\sigma}{\sqrt{n}}}$

$0.9 = P(|Z|$

For a confidence level of 90% our $Z_{critic}$ is 1.645

Therefore,

$\frac{0.1}{\frac{\sigma}{\sqrt{n}}} = 1.645$

Substituting for $\sigma = 5$ and re-arrange for n, we have that n is equal to

$n=(\frac{1.645\sigma}{0.1})^2$

$n=\frac{(1.645)^2(0.5)^2}{0.1^2}$

$n=67.65$

$n=68$

We need to make 68 readings for have a probability of 90% and our average is within $0.1\°\frac$

3 0

2 years ago

Electro-magnets are created by...

mojhsa [17]

Wrapping in insulated wire around a medal with ferromagnetic properties and applying an electric current

6 0

2 years ago