Physics Easy 10 points?

2016-08-01 1:23 am
1. A certain string breaks when a force of 200 N is exerted on it. If two people pull on opposite ends of the string each with a force of 180 , will the string break ? Explain ?


2. In an experiment to determine the value of π, a cylinder is measured to have an average value of 4.2 cm for it's diameter and average value of 13.00 cm for it's circumference. If the accepted valued of π is 3.1416, what is the percent error of the experiment value.

回答 (3)

2016-08-01 4:14 am
✔ 最佳答案
1. If two people pull on opposite sides of the string with a force of 180 N, then the tension in the string is 180 N. (Not 360 N!) This string does not break.

2. experiment: π_e = c / d = 13.00cm / 4.2cm = 3.1
(only 2 significant digits allowed, owing to "4.2 cm."

%error = 100% * (π - π_e) / π = 1.3%

Hope this helps!
2016-08-01 3:41 am
1. A certain string breaks when a force of 200 N is exerted on it. If two people pull on opposite ends of the string each with a force of 180 , will the string break ? Explain ?

2 * 180 = 360 N
Since this is greater than 200 N, the string will break.

2. In an experiment to determine the value of π, a cylinder is measured to have an average value of 4.2 cm for it's diameter and average value of 13.00 cm for it's circumference. If the accepted valued of π is 3.1416, what is the percent error of the experiment value.

Circumference = π * d
13 = x * 4.2
x = 13 ÷ 4.2
This is approximately 3.095 cm.

% error = 100 * [3.1416 – (13 ÷ 4.2)] ÷ 3.1416
This is approximately 14.6% error
2016-08-01 1:23 am
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