In terms of motion, when a jet fighter is sitting stationary on the tarmac it has something in common with when it's flying on a straight course at 3000 km/h. Explain?

1 Answer
Mar 29, 2018

It's acceleration is zero


The key here is that it is flying on a straight course at 3000 km/h. Obviously that is very fast. However, if that velocity is not changing, it's acceleration is zero.

The reason we know that is acceleration is defined as #{\Delta velocity}/{\Delta time}#

So, if there is no change in velocity, the numerator is zero, and therefore the answer (acceleration) is zero.

While the plane is sitting on the the tarmac, it's acceleration is also zero. While the acceleration due to gravity is present and trying to pull the plane down to the center of the earth, the Normal Force provided by the tarmac is pushing up with equal magnitude.

Then, if the object is sitting still, that means that it's velocity is zero because velocity is #{\Delta position}/{\Delta time}#

So, if it's not moving, both its velocity and acceleration are zero