A motorboat is driven across a river at 3.0 km/h at a right angle to the current, which is flowing at 10 km/h. Sketch a diagram of this problem labeling each vector, then calculate the resultant vector.

The gun from the crime scene shows tool marks where the serial numbers are ground off. there are also tool marks on the bullets left behind. what information can the tool marks on the bullets and gun provide about the crime? what type of evidence does this information provide, individual or class?