U7 WS 3: Conservation of Momentum & Loops 1. A 258-g block of wood is at rest at the bottom of a loop-the-loop section of track when it is struck by a 5-g bullet initially moving at speed v. Upon impact the bullet becomes embedded in the wood. a. How fast was the bullet traveling prior to striking the block if the bullet/block combination just slides through the top of the loop-the-loop without losing contact with the track? Ignore friction. r = 40 cm 2. A 400 meter radius curve is banked at 120. We'll define the critical velocity as the velocity required to keep the car traveling on the curve without friction. a. What would be the two forces acting on a car that is traveling through this banked curve at its critical velocity? b. What force is supplying the centripetal force to keep the car moving in its 123 circular path? c. . What is the critical velocity of a car traveling through this curve? (28.9) d. If a car were to travel at this same speed through a regular flat curve having this same radius, how large would the coefficient of friction need to be to maintain its contact with the road surface? (.213)