Explain 8. How do you know that
the bicyclists in the first
panel above are moving
at a constant velocity?

Constant velocity means that the object in motion is moving in a straight line at a constant speed. You know this as in the first panel each arrow representing each second is the same width apart, therefore you know the cyclists are moving at a constant velocity. Compare this to the second box representing changing speed. The arrows are different lengths meaning each second the cyclists are moving at a different speed and are not moving at a constant velocity.

Hope this helped.

he kicked it 10 feet straight up into the air? i think this works.