# Physics help please?

Determine the overall tension in string required to rotate a 50. kg object in a horizontal radius of 0.50 m in the air with a period of 0.75 s. Determine the angle to the vertical at which the string will be rotated. Provide a complete solution using proper form of communication

### 1 Answer

- billrussell42Lv 71 month agoFavorite Answer
period of 0.75 s means rotation rate of 1 rev/0.75s

1 rev/0.75s x 2π rad/rev = ω = 8.38 rad/s

Centripetal force f = mrω² = 50•0.5•8.38² = 1755 N

force due to weight = mg = 50•9.8 = 490 N

the two are orthogonal, so net is √(490² + 1755²) = 1822 N which is tension.

angle with vertical is arctan (1755/490) = 74.4º

what is "proper form of communication" ??

or better yet, what is improper form of communication ?

Centripetal force f = mV²/r = mrω²

ω is angular velocity in radians/sec

1 radian/sec = 9.55 rev/min

m is mass in kg

r is radius of circle in meters

V is the tangental velocity in m/s = ωr

f is in Newtons