A BODY FROM the top of the tower takes 2.0(+-)0.1s to fall to the ground.The acceleration due to gravity 10 ms^-2 .
What is the height of the tower.
The diameter of a wire is 0.56(+-) mm What is the cross-sectional area of the wire?
The mass and diameter of a ball were used to determine its density. The mass was measured within 1% and the diameter within 3 % What is the percentage error in the calculated density of steel ball.
The force on a small disc placed in the centre of a pipe perpendicular to the liquid flow is dependent on the velocity of the liquid in the pipe. The force is related to velocity as shown .
Force= Constant * (Velocity)^2
If the velocity is to be found with a max. error of 1% find the max. % error in measuring the force.
F6 Phy
2009-07-16 9:45 pm
回答 (1)
2009-07-17 1:29 am
✔ 最佳答案
1. By s = 1/2 at2Height, s = 1/2 (10)(2.0)2 = 20.0 m
By │ &s / s│ = 2│&t / t│
&s / 20 = 2(0.1/2.0)
Uncertainty in height, &s = 2.0 m
So, the height, s = 20.0 +- 2.0 m
2. I assume the uncertainty in diameter is 0.01 mm
Cross-sectional area, A = pi(d/2)2 = pi(0.56/2)2 = 0.246 mm2
By │&A / A│ = 2│&d / d│
&A / 0.25 = 2(0.01/0.56)
Uncertainty in area, &A = 0.009 mm2
So, the cross sectional area, A = 0.246 +- 0.009 mm2
3. By Mass = density X volume
density, p = 4/3 pi(d/2)3 / m
│&p / p│ = 3│&d / d│ + │&m / m│
Percentage error in density = 3(3%) + 1% = 10%
4. │&F / F│ = 2│&v / v│
Max. % error in force = 2(1%) = 2%
參考: Physics king
收錄日期: 2021-04-19 15:04:23
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