Question

A kid at the junior high cafeteria wants to propel an empty milk carton along a lunch table by hitting it with a 3.1 g spit ball

If he wants the speed of the 40 g carton just after the spit ball hits it to be 0.31 m/s , at what speed should his 3.1 g spit ball hit the carton?

Answer 1

Consider the law of conservation momentum, ere mi, m, - Mass in kg u2-Initial velocity i, -Final velocity Thus, the momentum before the collision is equal to momentum after the collision The initial velocity of m ieu2-0 Therefore, the equation (1) becomes, 1-е ere, v - Final velocity in m/s Substitute, 3.1 g for m, , 40 g for m2 and 0.31 m/s for v in equation (2) 3.1xu (3.1+40)x0.31 3.1xuj -13.361 13.361 4.31m/s Thus, the speed should 3.1 g spit ball hit the carton is u 4.31m/s