Jerk: derivative of acceleration

[jordanfc]

If I was driving in a car how could I differentiate between jerk and acceleration? How does jerk feel compared to acceleration? Also, at what instances is jerk noticeable? (I'd imagine coming to a complete stop and maybe shifting gears?)

[Kygron]

When you accelerate you notice that you are pressed into the backrest of your seat. As you change in acceleration you feel yourself moving further into (or out of) your seat. When I drive I like to accelerate this "rate of seat compression" so that it feels more natural.

[mezarashi]

Any "jerks" you feel while driving is caused by acceleration. There is a difference in velocity (speed) between the car and your body. Acceleration is defined as a change in velocity. You "feel" acceleration when a force is exerted as a result onto your body. (In fact acceleration is caused by force)

 

To understand this fully well, just understand that all objects tend to continue in their state of motion unless acted on by a force. Meaning that when you press the acceletor, your car speeds up, but your body wants to continue at the slow speed. You feel the pressure of the of the seat behind you pushin on your back so you go faster and finally attain the same speed as the car. If you suddenly hit the breaks or do anything to change the car's velocity, you'll soon feel "jerks" because your body doesn't want to change its velocity.

[swansont]

Any "jerks" you feel while driving is caused by acceleration. There is a difference in velocity (speed) between the car and your body. Acceleration is defined as a change in velocity. You "feel" acceleration when a force is exerted as a result onto your body. (In fact acceleration is caused by force)

 

To understand this fully well' date=' just understand that all objects tend to continue in their state of motion unless acted on by a force. Meaning that when you press the acceletor, your car speeds up, but your body wants to continue at the slow speed. You feel the pressure of the of the seat behind you pushin on your back so you go faster and finally attain the same speed as the car. If you suddenly hit the breaks or do anything to change the car's velocity, you'll soon feel "jerks" because your body doesn't want to change its velocity.[/quote']

 

"jerk" is defined in physics as the derivative of acceleration. The OP was asking about that, AFAIK, not the sensation.

[mezarashi]

LoL, my bad completely. I would say that you will have a difficult time differentiating acceleration and jerk. The only possible sensible parameter I'd say our human bodies can judge is like Kygron said, force. Since acceleration is proportional to force, any change in the force exerted on you (most probably by your seat) can indication this change in acceleration.