Physics AP
posted by Robert on .
A conical pendulum is formed by attaching a 50 g mass to a 1.2m string. The mass swings around a circle of radius 25cm. A claculate the speed of the mass. B Calculate the acceleration of the mass. C calculate the tension in the string

cos φ=0.25/1.2 =0.208 => φ=78°
sinφ=0.98, tan φ=4.7.
x: ma=Tcosφ
y: 0=Tsinφmg
a=v²/R,
Tsinφ=mg
Tcosφ= mv²/R
Tsinφ/Tcosφ= mgR/ mv²
tanφ= gR/v²
v=sqrt{gR/tanφ}=sqrt(9.8•0.25/4.7) =0.72 m/s
a= v²/R=0.72²/0.25=2.1 m.s²
T=mg/sinφ=0.05•9.8/0.98 = 0.5 N