Force changes
motion.
Predict first. Fire opposing thrusters. Watch acceleration change velocity, then disappear while the cart keeps moving.
NET FORCE20.0 N
ACCELERATION0.00 m/s^2
VELOCITY0.00 m/s
MASTERY0 / 4
THE PRECISE ANSWER
Force does not create velocity.
Net force creates acceleration. Acceleration changes velocity. Velocity changes position. When net force becomes zero, acceleration becomes zero, but velocity does not have to disappear.
Why subtract the thrusters?
Force has direction. Opposing forces cancel, so the cart responds only to F_right - F_left.
Why does mass matter?
Mass measures resistance to acceleration. At the same net force, twice the mass produces half the acceleration.
Why can the cart coast?
Zero net force means zero acceleration, not zero velocity. In this ideal model, a moving cart keeps its velocity after thrust ends.