6. Once it is kicked, the soccer ball’s inertia will keep it going because the ball RESISTS changing its motion. If the ball doesn’t hit anything, the forces of gravity and friction will eventually stop the ball. On Earth, gravity and friction are unbalanced forces that often change an object’s motion.
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12. Force = mass x acceleration If you think about force and mass/acceleration as being on opposite sides of a teeter-totter, you always want to keep them balanced. If you make F larger or smaller, then m or a or both of them will have to change. If F stays the same and m gets larger, a will obviously have to get smaller for things to stay in balance. If m gets smaller, then a has to get larger.
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15. What is Acceleration? The speeding up, slowing down, or change in direction of an object. Acceleration is affected by the forces applied to objects as well as the mass of the objects in question. Acceleration = Force / Mass (If you double the mass of an object you cut the acceleration in half) Objects with lots of inertia have a large mass and objects with little inertia have a smaller mass
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19. Weightlessness Remember, objects in free fall only have the force of gravity pulling them downward (ignoring friction of course!) Astronauts are not really weightless in space; they just feel like they are because they are so far from earth’s core (gravitational pull). (force) Weight = M x Accel.
Motorcycles have less mass and have more acceleration (or deceleration) than cars. Therefore, it takes less force to stop them and they will stop faster than a car. If you ride too close, you could easily hit one. Newton’s 2 nd Law says that you are changing velocity faster on a sharp curve because you are changing direction faster. A faster change in direction means greater acceleration, which requires more force. More force means more friction between the tires and the road. More friction means that the tires will wear out faster on sharp curves than on gradual curves.
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