It's been 50 years since I took high school physics, but I saw something yesterday that got me thinking about the Force equation F=ma, particularly the acceleration part. On the side of the road I saw a car that had obviously hit something a high velocity. The front end was almost completely destroyed, with the hood bent almost in half and almost a 90 degree angle. My thought was there was a lot of force involved. With regard to the force and acceleration I thought there were 3 scenarios: 1. the car was accelerating; 2. the car might have been in cruise control, having a constant velocity but no acceleration; or 3. the car was attempting to slow down, and therefore de-accelerating. Thinking through the math, scenario 1 appears to be the only one where F is positive. Scenario 2, with zero acceleration indicates a force of zero, and scenario 3 indicates a negative force. I know this cannot be accurate, so what am I missing?
- Bill Morton (age 67)