Physics please help!
posted by Mary .
The distance between earth and the moon can be determined from the time it takes for a laser beam to travel from earth to a reflector on the moon and back. If the roundtrip time can be measured to an accuracy of 0.19 of a nanosecond (1 ns = 109 s), what is the corresponding error in the earthmoon distance?

Find the speed of light for the laser. How much distance error does 0.19 * 10^9 represent? Find how far the laser light travels in this time to find the error.

Find the maximum pressure that a gold brick can exert on the surface of a table by placing one of its faces flush against the surface?

I agree.