A Block on a Frictionless, Horizontal Surface Is Attached to One

Multiple Choice

A block on a frictionless, horizontal surface is attached to one end of a spring that is also attached to the wall on the opposite end. When stretched away from equilibrium by 15 cm and released, the block oscillates with a period of 0.25 s. If the mass of the block is 15 kg, what force was required to stretch the spring by the initial 15 cm?

A) 230 N
B) 450 N
C) 710 N
D) 360 N
E) 1400 N