(1) The principle of forward
A tennis ball is in a transparent acrylic ball. Due to the weight of the tennis ball, after being pushed, the movement of the tennis ball drives the movement of the acrylic ball.
(2) Build the car
(3)
Put in the car without electricity
When the car is connected to power
Since the weight of the car is not enough, need to push it from the outside to start the small ball. However, it cannot roll very far, and the car will tip over inside, making the ball completely unable to move. Still needs improvement.