A particle attached to a light string of length ℓ moves at constant speed v in a circle on a smooth horizontal table, with the string tied to a peg at the centre. The inward resultant force is (T denotes string tension):
Options

Question

A particle attached to a light string of length ℓ moves at constant speed v in a circle on a smooth horizontal table, with the string tied to a peg at the centre. The inward resultant force is (T denotes string tension):

Options

G1 Physics · Accepted Answer

For motion on a smooth horizontal table, gravity and normal cancel vertically. The only inward horizontal force is string tension T, so F꜀=T=mv²/ℓ. Do not add a separate "centripetal force" to tension: centripetal force names the net inward force. Answer: A.