How much force is needed to stop a 50 kg gymnast if he decelerates at 25 m/s^2

in net forces

An ideal transformer has 60 turns in its primary coil and 360 turns in its secondary coil. if the input rms voltage for the 60-turn coil is 120 v, what is the output rms voltage of the secondary coil?

Acar traveling at 22 m/s starts to decelerate steadily. it comes to a complete stop in 15 seconds. what is it’s acceleration?

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.