A car traveling at $45$ ft/sec begins decelerating (time is zero here, as is position) at a constant $10$ feet per second squared. How many feet does the car travel before coming to a complete stop? Yet another hint: is the acceleration positive or negative? Then, determine the velocity function by integrating the acceleration function, and solving for C (the fixed point will be the velocity of the car at t=0). Integrate the velocity function to determine the position function, and solve for C (the fixed point will be the position when t=0 - and I gave that info above). One more thing...to find how long it will take to stop (which you will need in order to determine how many feet it takes to stop) you will need to use the velocity function and solve for t when v(t)=0. whew!! Maybe not so easy?!?