A passenger of mass 90kg is involved in a minor car crash. The car approaches a solid barrier at 32m/s. It crashes into the barrer and stops in 0.2s. Determine the impulse that must be applied to the car to bring it to rest

The period of a pendulum varies directly as the square root of the length of the pendulum and inversely as the square root of the acceleration due to gravity. find the period when the length is 144 cm and the acceleration due to gravity is 980 cm per second squared, if the period is 7pi seconds when the length is 289 cm and the acceleration due to gravity is 980 cm per second squared.