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3 years ago

10

The atomic number of yttrium is 39. The atomic mass of one of its isotopes is 89. How many neutrons are in an atom of this isoto

pe?

1 answer:

gogolik [260]3 years ago

8 0

50. The atomic mass is essentially a tally of all of the atoms in the nucleus, since electrons are essentially negligible in mass.

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Early experiments with light were understood by explaining the behavior of light in terms of waves. Which experimental result re

STALIN [3.7K]

The answer to what experimental result required considering the particle nature of light is A. The ultraviolet catastrophe of blackbody radiation.

8 0

3 years ago

A very long train is rolling at 4 m/s along a straight track. An observer is standing on the ground very dangerously close to th

hichkok12 [17]

Answer:

A. $\vec{r}=(6\frac{m}{s})t\ \ \hat{i}$

B. t = 50 s

Explanation:

A. The vectorial equation of the person who is getting closer to the other person is:

$\vec{r}=\vec{v}t$

r: position vector

v: speed vector = 6m/s i (if you consider the motion as a horizontal motion)

Then, you replace and obtain:

$\vec{r}=(6\frac{m}{s})t\ \ \hat{i}$

B. The time is:

$t=\frac{d}{v}$

d: distance to the observer = 300m

v: speed of the person on the car = 6.00 m/s

$t=\frac{300m}{6m/s}=50s$

4 0

3 years ago

PLEASE HELP ASAP...TIMED TEST. PLEASE ANSWER WITH AT LEAST A PARAGRAPH!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

charle [14.2K]

Answer: I am pretty sure that you should pick radio waves.

Explanation: The scientist should use radio waves. I think this because you can use the radio waves to analyze the signals from outer space. This will work much better than anything there, to analyze it the best possible.

The best I could do.

8 0

3 years ago

27.0 mL to the nearest milliliter

Mila [183]

Answer:

27.0 milliliters is the nearest mililiter so 27.0 is the answer

Explanation:

8 0

3 years ago

Two boats start together and race across a 48-km-wide lake and back. boat a goes across at 48 km/h and returns at 48 km/h. boat

jolli1 [7]

Answer:

Time required by boat 1 for the round trip is less than that of boat 2.

Hence, boat 1 wins.

Explanation:

Case 1: Boat 1

Speed of boat = $\frac{distance of river}{time}$

time = $\frac{distance of river}{speed of boat}$

While going to another end

time = $\frac{distance of river}{speed of boat}$

time = $\frac{48}{48}$

time = 1 hour

While going back,

time = $\frac{distance of river}{speed of boat}$

time = $\frac{48}{48}$

time = 1 hour

Total time taken by boat 1 is,

Total time by boat 1 = 1 hour + 1 hour = 2 hour

Total time by boat 1 = 2 hour

Total time taken by boat 1 for the round trip is 2 hour.

Case 2: Boat 2

Speed of boat = $\frac{distance of river}{time}$

time = $\frac{distance of river}{speed of boat}$

While going to another end

time = $\frac{distance of river}{speed of boat}$

time = $\frac{48}{24}$

time = 2 hour

While going back,

time = $\frac{distance of river}{speed of boat}$

time = $\frac{48}{72}$

time = 0.66 hour

Total time taken by boat 2 is,

Total time by boat 1 = 2 hour + 0.66 hour

Total time by boat 1 = 2.66 hour

Total time taken by boat 2 for the round trip is 2.66 hour.

Time required by boat 1 for the round trip is less than that of boat 2.

Hence, boat 1 wins.

5 0

3 years ago