posted by JJ on .
Indentify the direction of the netforce in each of the following situations.
A marble moves in a circular path inside a paper plate at a constant speed.
The moon orbits the earth.
An air hockey puck moves smoothly across the air hockey table after being struck.
A rocket is launched upward from the launch pad.
There is a net force inward on the marble m v^2/R
There is a net force inward (toward earth) on the moon
there is no net horizontal force on the puck. It is not accelerating.
There is a net force up on the rocket
F = change of momentum per second = mass per second of exhaust * speed of exhaust