A 2100 lb (1 kg=2.2 lbs) car is using 4500 N of traction in order to move with a constant velocity of 67 mph (29.8 m/s). What is the acceleration of this 9300 N vehicle?

Explanation:

The acceleration of a body is defined as the change in velocity of an object, with respect to time. So, in order to produce and acceleration in any object, the velocity of that object must change. And, if the velocity of the object is not changing with respect to time, then the object is said to have a uniform motion. The acceleration of the object in such uniform motion is always zero. Because the change in velocity is zero.

Since, the car in this case is moving with a constant speed. Therefore, its acceleration will also be zero.

a = 0 m/s²

if the thermos has a vacuum innner, then heat through conv currents and conduction are reduced = vacuum flask

i don't understand. explain it clearly