A parachute on a racing dragster opens and changes the speed of the car from 85 m/s to 45 m/s in a period of 0.1 minute. What is the acceleration of the dragster?

I’m not sure about this question

A) the moment of inertia is given by i = mr^2 here m = 0.25 and r = 0.5. i = 0.25 * (0.5)^2 = 0.0625. b) i = 9.74 * 10^(37) and mass = 5.98 * 10^(24) so r^2 = i/m = 9.74 * 10^(37)/5.98 * 10^(24) = 1.628 * 10^(37 - 24) = 1.628 * 10^(13) r = √ 1.628 * 10^(13) = 4034848.200 c) since angular momentum is the product of moment of inertia and angular velocity, a = i * v; but i = mr^2 = 2 * 0.6^2 = 0.72 so a = 0.72 * 1.1 = 0.792. if she pulls her hand in 0.15 m. the new radius = 0.6 - 0.15 = 0.45. v = angular momentum/ radius = 0.792/ 0.45 = 1.76