Answer:At momentum = mass • velocity impulse = Force • Time Interval i. [kg•m/s] [kg] [m/s] ... IFK To determine which formula to use, find your knowns and unknowns. ... A deer with a mass of 146 kg is running head-on toward you with a speed of 17 m/s. You are going north. ... At=1.5 5 3(1.5) =0.5( VF-D) 4.5= 0.5 VE VE = 9 m/s.