Is the Earth’s rotation used as a standard of time?

Question

lastdaywork · Answer

We need a repetitive event to measure time and the most obvious one was the cycle of day and night. As scientists got nerdier; they started looking for a reason to believe that a certain repetition is periodic and hence kept looking for a fundamental property. On present day, time is measured by atomic properties. See - http://physics.nist.gov/cuu/Units/current.html

anonymous · Answer

so no?

lastdaywork · Answer

Was this a true/false question ??

anonymous · Answer

it is a yes or no question

lastdaywork · Answer

No

anonymous · Answer

A vector is drawn with its tail at the origin of an xy coordinate system. In which quadrant does the vector point if the angle with respect to the positive direction of an x axis is -135°?since quadrant 3 is between -90 to -180, so the answer would be quadrant 3, right?

lastdaywork · Answer

Correct

anonymous · Answer

What is the direction of the result of the cross product of vectors a and b? is perpendicular to the plane of vectors a and b, correct?

lastdaywork · Answer

Are you planning to complete your homework via this website ??

anonymous · Answer

no, i only have one chance to submit the answer, and i did the problem,so i just want to make sure i didn't miss anything