Physics Easy 10 points ?

2016-07-31 10:05 pm
1. When multiplying several quantities, the number of significant digits in the result must always be?

A. larger then the number of significant digits in the most accurate of quantities.

B. equal to the number of significant digits in the most accurate of quantities.

C. equal to the average number of significant digits in the most and least accurate of the quantities.

D. equal to the number of significant of significant digits in the least accurate of the quantities.

E. smaller than the number of significant digits in the accurate of the quantities.


2.When dividing several quantities,the number of significant digits in the results must always be?

A larger then the number of significant digits in the most accurate of quantities.

B equal to the number of significant digits in the most accurate of quantities.

C equal to the average number of significant digits in the most and least accurate of the quantities

D equal to the number of significant of significant digits in the least accurate of the quantities

E smaller than the number of significant digits in the accurate of the quantities



3. A ball of mass m1 = 30 kg traveling west with a velocity v1 = 500 cm/sec collides head on with a ball of mass m2 = 15 kg traveling due west with a velocity v2 = 300 cm/sec. If the first mass leaves the event due west at 3 m/s calculate the velocity of the second mass


A 0 m/s

B 5 m/s due west

C 7 m/s due east

D 13 m/s due east

E 25 m/s due east

回答 (2)

2016-07-31 10:30 pm
✔ 最佳答案
1. D. equal to the number of significant of significant digits in the least accurate of the quantities.

2. D equal to the number of significant of significant digits in the least accurate of the quantities

3. Conserve momentum:
30kg * 500cm/s - 15kg * 300cm/s = 30kg * -300cm/s + 15kg * V
V = 1300 cm/s = 13 m/s
and positive means "east." ◄ D

You must either convert all velocities to cm/s or to m/s, but don't mix them.

Hope this helps!
2016-07-31 10:11 pm
Equal to significant figures than the least significant number.

If 3.2345 * 5.66666 * 7.0 then your answer would only have 2 SigFig.


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