Tuesday

September 30, 2014

September 30, 2014

Posted by **jake** on Thursday, January 13, 2011 at 10:05pm.

In which of the following processes is there a decrease in the potential energy of the substances involved?

A) a coil spring is compressed

B) two particles of opposite charge are separated

C) photosynthesis produces glucose from carbon dioxide and water

D) liquid water evaporates to form water vapor

E) methane gas burns in oxygen to form carbon dioxide and water

The speed of light is 3.0 x 108 m/s. How many milliseconds does it take for a light signal from earth to reach and return from a satellite that is in orbit 30 miles above the earth? (1 millisecond = 10-3 seconds)

A) 320 milliseconds

B) 16 milliseconds

C) 32 milliseconds

D) 0.32 milliseconds

E) 0.16 milliseconds

No one has answered this question yet.

- chemistry -
**Dr Russ**, Friday, January 14, 2011 at 6:54amConvert miles to metres

1 miles = 1 609.344 metres

so

distance = 30 miles x 1 609.344 metres mile^-1

=48280.32 m

time taken = distance/velocity

=48280.32 m/ 3.0 x 10^8 m s^-1= 0.0001609 s or 0.16 ms

- chemistry -
**D**, Saturday, February 12, 2011 at 7:50pmSorry Doc but the satallite is 30 miles above the earth and the question states there and back. please check again.

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