An ideal massless spring S can be compressed by 1 m by a force of 100 N in equilibrium. The same spring is placed at the bottom of a frictionless inclined plane at 30∘ to the horizontal. A 10 kg block M is released from rest at the top of the incline and is brought to rest momentarily after compressing the spring by 2 m. If g=10 m/s2, what is the speed of mass just before it touches the spring?