What is the Speed and Tension?

A 260 g block on a 60 cm-long string swings in a circle on a horizontal, frictionless table at 60 rpm.

1) What is the speed of the block?

Known variables:

Mass (m): 260 g or .26 kg

Radius (r): 60 cm or .6m

Period (T): 60 rpm

Speed Equation

v = ω r
Convert to radians

ω = 60 rpm

Angular Velocity:

ω=2π/T

60  x  2π/60 = 6.283 rad/s

v = ω r
v = 6.283 * 0.60 = 3.7699 m/s

v=3.8m/s

2) What is the tension in the string?

Equations for Tension:

T = mv²/r

0.26 x (3.7699²) / 0.60

T = 6.2 N