A person in his car is going at the right at 52 m/s when he slams into the boulder. Person's mass along with the car is 159 kg and boulder's mass is 489 kg. The boulder is stationary at first but when the impact on it was received it started to fall to the ground with a gravity/acceleration of -9.81 m/s^2. What is the person's final velocity after the collision? For this question, we need to use the inelastic collision equation, but not understanding how to use it given all this information. Equation goes as follows : m1(vi1) + m2(vi2) = vf(m1+m2) where m1 = mass of object 1, m2 = mass of object 2, vi1 = initial velocity of object 1, vi2 = initial velocity of object 2, vf = final velocity