I can't get these at all... 1) A sprinter with a mass of 76 kg accelerates force 0 to 9.4 m/s in 2.8 s. Find the average force acting on the runner. 2) A 0.25 kg soccer ball is rolling at 6.0 m/s towards a player. The player kicks the ball back in the opposite direction and gives it a velocity of -14 m/s. What is the average force during the interaction between the player's foot and the ball if the interaction lasts 2.0 x 10 to -2 s. 3) A force of 1.21 x 10 to 3 N is needed to bring a car moving at +22.0 m/s to a halt in 20.0 s? What is the mass of the car? 4) Small rockets are used to make small adjustments in the speed of satellites. ONe such rocket has thrust of 35 N. If it is fired to change the velocity of 72 000 kg spacecraft by 63 cm/s, how long should it be fired? 5) A 10 000 kg freight car is rolling along a track at 3.00 m/s. Calculate the time needed for a force of 1000 N to stop the car. 6) A car moving at 10 m/s crashes into a barrier and stops in 0.24m. a) Find the time required to stop the car. b) If a 20 kg child were to be stopped in the same time as the car, what average force must be exerted? c) Approximately waht is the mass of an object whose weight equals the force from part b? Could you lift such a mass with your arm? d) What does your answer to part c say about holding a infant on your lap instead of using a separate infant restraint?