consider a dynamics problem in which a rocket is modeled as a wheeled vehicle on rails. the vehicle has a mass of 1000 kg and carries 1000 kg of bricks, each having a mass of 1 kg. the bricks are ejected from the back of the vehicle at a speed relative to the cart of 100 m/s. if all of the bricks are ejected nearly instantaneously over approximately a 100 msec time frame, calculate the final velocity of the cart. if the bricks are ejected one at a time at 100 m/s, calculate the final velocity of the cart. if the bricks were ground up into a fine powder and sprayed out the back at the same 100 m/s, calculate the final velocity of the cart. does it matter how much time it takes to eject the brick material at 100 m/s? if the bricks in b are ejected in 1 second intervals, estimate and plot the average acceleration of the cart as a function of time and compare this to the approximate average acceleration resulting from part a.