How Does Weight Affect Speed?
An object with more weight resists any change in its speed and has a greater tendency to maintain its motion. This is because an object with more weight is more massive, and an object that is massive has more inertia that causes it to resist any change in speed.
Newton's first law of motion states that an object at rest stays at rest and an object in motion stays in motion, unless that object is acted upon by an unbalanced force. This force overcomes any resistive forces, such as friction, in order to cause acceleration. Acceleration causes an object to change its speed or its direction of motion.
Newton's second law states that a force is a product of an object's mass multiplied by an object's acceleration. Weight itself is a type of force in which the acceleration on the object is due to the effect of Earth's gravity. Since this acceleration is constant, the object's weight is directly related to the object's mass. An increase in an object's weight also increases resistive forces, such as friction, which makes it more difficult for an object to gain speed at rest and increases the tendency for the object to lose speed while in motion.