A daredevil jumps off the CN Tower and falls freely for several seconds before releasing his parachute. His height, h, in meters, t seconds after jumping can be modeled by: h=-4.9t^2+t+360 before he released his parachute; and h= -4t +142 after he released his parachute.

How long after jumping did the daredevil release his parachute?

Amass weighing 16 pounds stretches a spring 8/3 feet. the mass is initially released from rest from a point 2 feet below the equilibrium position, and the subsequent motion takes place in a medium that offers a damping force that is numerically equal to 1/2 the instantaneous velocity. find the equation of motion if the mass is driven by an external force equal to f(t)=cos(2t).