How would you calculate the spring constant of an unknown spring?

The least penetrating form of radiation is

Suppose a comet has an orbital period of 309.1 years around the sun. what is it’s average distance from the sun?

Amachinist turns the power on to a grinding wheel, at rest, at time t = 0 s. the wheel accelerates uniformly for 10 s and reaches the operating angular velocity of 96 rad/s. the wheel is run at that angular velocity for 40 s and then power is shut off. the wheel slows down uniformly at 1.5 rad/s2 until the wheel stops. in this situation, the time interval of deceleration is closest to: