Inertia, gravity, friction.
The forces acting on the bike is gravity, air resistance and friction.
forces that are active derr
Active forces are physical forces that create motion or an acceleration in a system, such as pushing or pulling. Reactive forces are the equal and opposite forces that result from the interaction of active forces, as described by Newton's third law of motion. Together, active and reactive forces explain the dynamics of objects in motion.
gravity
The bike that you should think of buying an active 9 year old is a 24-inch wheel bike.
The sentence "The eggs were thrown" is in the passive voice, as the subject (eggs) receives the action (thrown) rather than performing it.
ALOT!!
When the bike is not moving, there is an equal force between the bike and a surface. If you are seated on the bike in a still position, you and the bike would create an even balanced force. If you accelerated, you would create an unbalanced force.
friction
Basketball needs forces so the ball is able to be thrown to the ring or another player.
The best bike to buy for a nine year old active boy is a 24in-wheel bike with a 3-speed hub gear.
A moving bicycle or bike will not fall when the opposing forces are balanced.