✔ 最佳答案
1. 6 revolution per second = 6 x2.pi radians/s = 37.7 radians/s
Centripetal force (向心力) needed = (5/g).R.(37.7^2)
where g is the acceleration due to gravity, taken to be 10 m/s2
R is the maximum radial distance from the centre.
The centripetal force is provided by friction, hence
(5/g).R.(37.7^2) = 2
solve for R gives R = 2.81 x 10^-3 m = 0.28 cm
2. What do you like to calculate?
2012-03-26 19:49:28 補充:
2. 10.sin(◎) = (0.4).R.w^2
where R is the radius of the circle and w is the angular velocity (角速度)
but R = 1 x sin(◎)
hence, 10.sin(◎) = (0.4).sin(◎).w^2
w = square-root[10/0.4] s^-1 = 5 s^-1
2012-03-26 19:52:45 補充:
1. Your equation: 2=5(r)37.7^2 is wrong
It should be 2=(5/g).(r)37.7^2
since 5 N is the weight, (5/g) is the mass of the cube
r = (2g/5)/(37.7)^2 m = 2.81x10^-3 m