Physicists— scientists who specialize in physics—have discovered that all objects in the world obey certain rules, or laws, when As soon as a player throws the ball, gravity starts pulling it down. Shown here: Lauren Jackson gets a pass off past a defender. His father, a farmer, died a few months before Isaac was born. His family tried to very ggood ood oo get the teenaged Isaac to take up farming, but he wass not very int nter eres er e te tedd inn at it. He went to Cambridge University, where he got interested mathematics and science.
Later, LLat ater at e , he er Newton eventually became a professor at Cambridge. He made many discoveries math ws of m otio ot ionn an io andd and science. According too legend, began wton ddied i d inn Newton forces act on them. Three key laws were described by the English scientist Isaac Newton in the s. Take, for example, a moving on moving in the same direction and at the same speed unless a ball.
It will keep on going at the force acts on it. The same idea applies to a ball or other object that is not moving. Such an object has zero speed and is said to be at rest. An object at rest will start moving only if some force causes it to. Of course, on Earth a real ball that is moving through the air sooner or later always comes to a stop.
This is because forces act on it. If one player passes the ball, the player making the catch stops the ball by applying force.
It is the combination of speed and direction. Using velocity in this way makes it possible to say the first law of motion very simply: an object will change its velocity only if a force acts on it. This uses the idea of inertia. Inertia is resistance to a change in movement. They did make it into the playoffs that year. Their first-round opponent was the Cleveland Cavaliers, who had finished ahead of the Bulls in the regular-season standings.
Chicago and Cleveland fought hard right up to the closing seconds of the fifth and deciding game of the series. Jordan got the ball, dribbled for position, and jumped in order to take a shot.
Jordan waited, seeming to hang in the air, until Ehlo was no longer in the way, and then he shot. The ball went through the net, and the Bulls won. The victory was a sign they were moving up in the basketball world. Just two years later, Jordan led them to their first NBA title.
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Jordan was born in in Brooklyn, New York. His family soon moved to Wilmington, North Carolina. There, he played on his high m. After trying his hand at baseball, he returned too the nd In In all all six six them to another three straight titles in , , and es during ng his his career car aree e r championship finals, he was named the MVP. Five times , and and When basketball players jump, they usually get no more than about 3 feet 90 centimeters above the floor before they start going down.
The hang time for a 4-foot jump is about one second, no matter who jumps. The hang time for a 3-foot jump is a little less. Jumpers like Jordan only look like they have a long hang time. In other words, their long hang time is an illusion. One thing that makes their hang time seem longer is that they hold on to the ball longer. Jordan often pulled his legs up during a jump.
This also made it seem he was staying really high. Stretching out an arm or moving the ball around during the jump can make the hang time seem longer, too. Sometimes they move forward or backward as well as up. This is because gravity pulls straight down. One is an upward, or vertical, velocity. The other is a velocity in a horizontal direction—that is, parallel with the floor.
It pulls only downward. Jump Force In order to jump, a player has to apply a force to the floor.
Of course, how high a jumper goes will depend on how strong the force is. The harder that jumpers push against the floor, the higher they can go before gravity pulls them back down. Mass is simply the amount of matter an object has. Heavy objects have more mass than light ones.
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If two players, one heavy and one not so heavy, use the same force in jumping, the lighter one will go higher. Newton came up with a second law that describes this and similar situations. It makes use greater the force, the greater the acceleration it gives to the object. Also, if the same force is used on In everyday life, people often objects of different mass, objects with use the word acceleration to less mass receive more acceleration. The change may be an increase or a decrease in speed, a change in direction, or a change in both speed and direction. One is the size of the force.
For any object, a stronger force will give it more acceleration. In other words, the more force Kobe Bryant uses when he makes a jump, the faster his velocity will be when he leaves the ground. The faster the velocity, the higher he will go before starting to come back down. The second thing that affects acceleration is the mass of the object. For any force, an object with less mass will receive more acceleration than an object with more mass. It is hard for really big players like Yao to jump high. They need to use a lot of force to move their mass.
Yao Ming right has more mass than Tracy McGrady left. For the two players to jump to the same height, Yao would have to use a lot more force. Weight and mass are related, but they actually are different things. Mass is the amount of matter the object has. So it makes sense to say that an object weighing 6 pounds 2.
But this gravity is the gravitational pull of Earth. Other bodies in the universe have a different gravity. If an object that weighs 6 pounds on Earth is taken to the Moon, it will weigh only about 1 pound 0. Sometimes forces cancel each other out. This is what happens when a basketball lies on the ground. The two forces are exactly balanced. Jumping is a different story.
When players jump, they push into the floor with enough force to overcome gravity. They leave the floor with a certain momentum.
Momentum is a way of measuring motion. It depends on both velocity and mass. But as soon as players leave the floor, their velocity starts decreasing. The main cause for the drop in velocity is gravity. Gravity never stops pulling downward. It causes jumpers to gradually lose momentum as they rise. At some point their momentum is no longer enough to overcome gravity, and they start going back down. As they drop, they go faster and faster, because gravity keeps accelerating them. In other words, for every action there is an equal and opposite reaction.
This third law of motion says every action has an equal and opposite reaction. The two forces are equal in amount, but they act in opposite directions. A jumper pushes into the ground with a certain force.