If the ball does not have a propeller or jet engine on it, then it is an object
in free fall. That means its downward speed grows by 9.8 m/s for every
second that it's in the air.
If it happens to be traveling upward at the moment, then that won't last long.
Its upward speed is decreasing by 9.8 m/s every second. It will eventually
run out of upward gas and start moving downward. At that instant, you might
say that the direction of its velocity has changed by 180 degrees.
Answer:
Mg or your weight.
Explanation:
When your velocity is constant, the net force acting on you is 0. That means the upwards force of air resistance must fully balance the downwards force of gravity on you, which is Mg.
Acceleration means speeding up, slowing down, or changing direction. The graph doesn't show anything about direction, so we just have to examine it for speeding up or slowing down ... any change of speed.
The y-axis of this graph IS speed. So the height of a point on the line is speed. If the line is going up or down, then speed is changing.
Sections a, c, and d are all going up or down. Section b is the only one where speed is not changing. So we can't be sure about b, because we don't know if the track may be curving ... the graph can't tell us that. But a, c, and d are DEFINITELY showing acceleration.
Answer:
0.006<357<700.003<6010<9256.0<9520.00