Your body is pushing down on a chair because it is being attracted by gravity, the reason that your body is not moving down because there is a normal force acting on your body; together the net force of weight (m*g) and normal force is equal to zero
Answer:
The tire fills up just like anything else that holds air when u pump a ball or tire up it fills all the way up cause it is a small confined space and after filling it with air the atoms of the air fill the tire up
Explanation:
V= s/t = 400/4.5=800/9 (km/h)
Answer:
The constriction causes the mercury column to break under tension, leaving a vacuum between the bottom of the column and that in the bulb, and the top of the column stays still at the position reached in the body - a "peak hold" system.
The position of the first ball is
while the position of the second ball, thrown with initial velocity 
, is
The time it takes for the first ball to reach the halfway point satisfies
We want the second ball to reach the same height at the same time, so that
