Monica found a clear mineral crystal. she wanted to identify its hardness. she tried to scratch it with her fingernail, a penny, and a steel nail but none of those worked. then she tried topaz, which did leave a scratch . the mineral was able to scratch glass. what mineral could monica have found? explain your answer.

Plz mark brainliest 30 points1) find the momentum of a 12 kg snowball that is rolling with a velocity of 9 m/s.2) an 8 ball with a mass of .5 kg is sitting at rest. it is hit by the cue ball (1 kg) traveling at 2.5 m/s. if the cue ball is at rest after the collision, how fast is the 8 ball traveling after the collision? 3) two football players are running toward each other. if the offensive player is 75 kg and is running 8 m/s, how fast must the 60 kg defensive player run in order for the two players to hit and stop?