Question

The force on an object F is the product of the mass and the acceleration: F=ma. In this case the mass and the acceleration both depend on time, hence so the does the force: F(t)=m(t)a(t). At time t=6 seconds the mass of an object is 45 grams and increasing at a rate of −7sg and the acceleration is 20ms2 and increasing at the rate −8ms3.

Using the product rule the force on the object is changing at the rate