(1 point) The force F on an object is the product of the mass m and the acceleration a. In this problem, assume that the mass and acceleration both depend on time t, hence so the does the force. That is, F(t) = m(t)a(t) At time t = 9 seconds, the mass of an object is 31 grams and changing at a rate of -5- . At this same time, the acceleration is 8- and changing at a rate of -42. By the product rule, the force on the object is changing at the rate of Please include units in your answer (click the link for help).. To enter compound units use multiplication, division, and exponent symbols, e.g., use fi*lb for foot-pounds or m/s*2 for meters per second per second