IN THESE CASES THERE IS NO NET EXTERNAL FORCE ON THE SYSTEM SO THE TOTAL SYSTEM
ID: 2187954 • Letter: I
Question
IN THESE CASES THERE IS NO NET EXTERNAL FORCE ON THE SYSTEM SO THE TOTAL SYSTEM MOMENTUM IS CONSERVED. THIS MEANS THAT YOU CAN USE THE FACT THAT THE TOTAL SYSTEM MOMENTUM HAS TO BE THE SAME AFTER AN INTERACTION AS IT WAS BEFORE TO FIND THE "UNKNOWN" QUANTITY IN THE QUESTION. Cart A has a mass of 3.00kg and is going to the right at the speed of 0.200 m/s and cart B has a mass of 2.00kg and is going to the left with a speed of 0.300m/s. They collide and cart A is seen to now be going to the left with a speed of 0.100m/s. A: What is the velocity of B after the collision? B: Do the same approach as problem A: The same two carts as above have the same initial velocities, but when they hit the ground they stick together, so that the final situation is essentially a big 5.00kg cart with some final momentum and velocity that you can find. C: Again say that the same two carts aollide, but say the initial Va,i=0.500m/s and Vb,i=-0.100m/s. The carts stick together as in part A. Find the velocity of the final 5.00kg composite cart. D: Now you have a 3.00 kg cart and a 2.00kg cart that are fastened together by a compressed spring. The 5.00kg composite cart is going to the right at a speed of 0.200m/s when the spring releases and pushes the carts apart. After this interaction the 3.00kg cart is seen to be going to the left at a speed of 0.100m/s. What is the speed 2.00kg cart after the collision? E: For all cases, use the impulse on cart A to find the average force on cart A assuming contact lasts 0.100s. PLEASE SHOW STEP BY STEPExplanation / Answer
conservation of momentum. (a) mAuA + mBuB = mAvA + mBvB => 3*0.2 - 2*0.3 = -3*0.1 + 2*vB => vB = 0.15 m/s towards right. (b) mAuA + mBuB = (mA + mB)v => 3*0.2 - 2*0.3 = (3 + 2)v => v = 0. (c) mAuA + mBuB = (mA + mB)v => 3*0.5 - 2*0.1 = (5)v => v = 0.26 m/s to right. (d) (mA + mB)u = mAvA + mBvB => 5*0.2 = -3*0.1 + 2*vB => vB = 0.65. (e) impulse = change in momentum. calculate change in momentum of cart A in every case as we already know the initial and final moments.