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3 years ago

A train travels 90 kilometers in 1 hours, and then 60 kilometers in 3 hours. What is its average speed

1 answer:

7 0

Average speed = (total distance) / (total time to cover the distance)

   = (90km + 60km) / (1hr + 3hr)

   = (150 km) / (4 hr)

   =    37.5 km/hr    .

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A negative charge -0.550 HC exerts an upward 0.700 N force on an unknown charge 0.220 m directly below it. (a) What is the unkno

Sonja [21]

Answer:

Part a)

$q_2 = -6.8 \mu C$

Part b)

$F = 0.700 N$

direction = downwards

Explanation:

As we know that the negative charge will experience the force due to some other charge below it

the force is given as

$F = 0.700 N$

now we know that

$F = \frac{kq_1q_2}{r^2}$

now plug in all data

$0.700 = \frac{(9 \times 10^9)(0.550\mu C)q_2}{0.220^2}$

$0.700 = 1.022\times 10^5 q_2$

$q_2 = -6.8 \mu C$

since this is a repulsion force so it must be a negative charge

Part b)

As per Newton's III law it will exert equal and opposite force on it

So here the force on the charge below it will be same in magnitude but opposite in direction

so here we have

$F = 0.700 N$

direction = downwards

4 0

3 years ago

Luis wanted to know which of his 4 toy cars is the fastest. He conducted an experime and recorded his results in the table shown

Murrr4er [49]

The dependent variable was the time and the independent variable was thecars

6 0

4 years ago

Tina has been dieting for a total of 13 weeks she lost 3 lb on the first week of her diet but gain the back of pound on the seco

PolarNik [594]

Answer:

D. 24 lb

Explanation:

Tina has been dieting for 13 weeks

First week she lost 3 pounds

Next week she gained 1 pound and did not lose any. This will be subtracted as she has gained a pound

The remaining 11 weeks she lost 2 pounds per week

Weight lost in the 11 weeks = 11×2 =22 pounds

Total weight lost

3-1+22 = 24 lb

Tina has lost 24 pounds in total during the 13 weeks

6 0

3 years ago

Which of the following statements about subatomic particles is FALSE? Which of the following statements about subatomic particle

kkurt [141]

Answer:

Protons have about the same mass as electrons is false

Explanation:

Electrons and protons have the same magnitude on charge but opposite sign

$e^{-}=-1.6\times10^{-19}C$ : charge of electron

$e^{+}=1.6\times10^{-19}C$ : charge of proton

Neutrons have no charge.

An atom is composed of protons and neutrons in the nucleus and electrons surrounding it, so a neutral atom has the same number of protons and electrons to has a net charge of zero. So, all the facts mentioned are true.

The false one is that protons have about the same mass as electrons, because the mass of an electron is $9.11\times10^{-31}kg$ and the mass of a proton is $1.67\times10^{-27}kg$ so the mass of a proton is a lot of bigger than electron mass.

8 0

3 years ago

1. A disturbance that is caused by vibrations and travels through a medium

Artemon [7]

Answer:

Sound

Explanation:

Sound is a longitudinal wave produced due to disturbance of particles of medium.

4 0

3 years ago