In the absence of external forces, an object at rest remains at rest and an object in motion continues in motion with a constant velocity (that is, with a constant speed in a straight line).
Card 6: Situation Involving Inertia 3 - Pulling a Thread
Pulling a Thread
Pull slowly - Thread A will snap. Explanation: Tension of thread A is higher than string B.
Tension at A = Weight of the load + Pulling Force
Yank quickly - Thread B will snap. Explanation:
The inertia of the load prevents the force from being transmitted to thread A, hence causing thread B to snap.
Bucket filled with sand is more difficult to be moved. It's also more difficult to be stopped from swinging.
Explanation:
Object with more mass offers a greater resistance to change from its state of motion.
Object with larger mass has larger inertiato resist the attempt to change the state of motion.
An empty cart is easier to be moved compare with a cart full with load. This is because a cart with larger mass has larger inertia to resist the attempt to change the state of motion.