a) Two cars race on a circular track with diameter of 1600m. One car travels at
a speed of 20 m/s and the other car travels at a speed of 22 m/s. How long will
it take the faster car to travel on lap more than the slower car?
b) Water flows through a 2 cm diameter horizontal pipe at a rate of 0.053
m^3s^-1.If the length of the pipe is 5 m and the output end is open to
atmospheric pressure. What is the pressure at the input?
physics problem
2010-04-06 7:25 pm
回答 (1)
2010-04-06 8:42 pm
✔ 最佳答案
(a) Relative velocity betweent the two cars = (22-20) m/s = 2 m/sHence, time required = distance/velocity = pi x 1600/2 s = 2513 s = 41.89 minutes
(b) using Poiseuille's formula,
0.053 = pi x P x (0.01)^4/8 x n x 5
where P is the pressure difference between the two ends of the pipe
n is the viscosity of water (= 1.3x10^-3 N-s/m2)
pi = 3.14159.....
solve for P
收錄日期: 2021-04-29 17:35:15
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