The speed of light is 3.0x105 km/sec, and it takes light 1.3 sec for light to travel from the moon to Earth.?

Question

From this information, what is the distance to the moon?

I'm stumped.

1. 390,000 km

2. 230,000 km

3. 3.9 km

4. 2.3 km

5. 4.3x105 km

Answer 1

If you know the speed and the time you can calculate the distance.

No different that "you are travelling at 100 km/hr, it takes you 2 hours to get where you are going, how far did you travel".

Distance = velocity / time.

Answer 2

#1 is the closest correct answer

Answer 3

the moon constantly moves away from us at a constant rate of 38 mm a year (thats about .1 mm a day)

PLUS!!!! the speed of light in a vacuum is actually 299,792.458 km/s -------------- not 3.0x105 km/sec

(numbers like that applied in mathematical equations causes mistakes and CAN KILL PEOPLE)

the moon (on an average of perigee and apogee) is about 384,000 km away from us.

the entire question could be considered misleading and incorrect in MANY ways. I'd present this argument to the teacher and school board and protest continuing begin graded on such incorrect information.

ok ok. I'll stop

# 1 is the only one that fits into where the moon could real be in todays reality.

(I don't know why she said v/t because its actually  v*t)

1.3 * 300000km = 390,000km

dividing would give you 230,000 but again this is an impossibility. the moon is at least 130,000 km further than that even when its at its closest.

Answer 4

The Moon is 356 334 kilometers (221 463 miles) away from Earth.

So none of your answers are correct.

You chose an interesting approach to calculate the distance.

The speed of light is 299 792 458 m/s and yes it takes 1.3 sec..

Answer 5

None are right, but given that info, the answer would be 409.3 the question just makes no sense.  

3.0 X 105 = 315

315 X1.3 = 409.3

something is missing

in the question could X be a variable