Force & Motion
Work, in physics, is a result of a force moving an object through a distance against a resistance. Work is always done by some agent, such as a person or a machine. This agent produces the force that causes the movement.
Force is also a push or a pull. In your everyday life, you experience a variety of forces. You apply a force to a ball when you throw it up in the air. As the ball rises, the force of gravity slows it down. As the ball descends, gravity makes it fall more rapidly. When you catch the ball, it applies a downward force to your hands. But your hands apply an upward force to the ball to stop it.
When a force occurs in one direction, there is always another equal force in the opposite direction. Energy that is stored as air in a blown up balloon is potential energy, when it is released it creates a force that moves the balloon in the opposite direction and becomes kinetic energy. The air in the balloon is gas under pressure. The air pushes against the balloon, causing it to expand, but the balloon is also pushing back on the air. When gas or liquid is under pressure, it tries to escape. In the case of the balloon, it escapes out the open end. In a rocket, it escapes through an opening called a nozzle. As the gas escapes, it creates the thrust that propels your rocket forward (or a real rocket upward). This is because of one of Newton's Laws of Motion: for every action, like gas escaping from a rocket in one direction, there is an equal and opposite reaction, like the rocket moving in the other direction.
Find out more about Isaac Newton's Laws of Motion by clicking on the link below:
Force is also a push or a pull. In your everyday life, you experience a variety of forces. You apply a force to a ball when you throw it up in the air. As the ball rises, the force of gravity slows it down. As the ball descends, gravity makes it fall more rapidly. When you catch the ball, it applies a downward force to your hands. But your hands apply an upward force to the ball to stop it.
When a force occurs in one direction, there is always another equal force in the opposite direction. Energy that is stored as air in a blown up balloon is potential energy, when it is released it creates a force that moves the balloon in the opposite direction and becomes kinetic energy. The air in the balloon is gas under pressure. The air pushes against the balloon, causing it to expand, but the balloon is also pushing back on the air. When gas or liquid is under pressure, it tries to escape. In the case of the balloon, it escapes out the open end. In a rocket, it escapes through an opening called a nozzle. As the gas escapes, it creates the thrust that propels your rocket forward (or a real rocket upward). This is because of one of Newton's Laws of Motion: for every action, like gas escaping from a rocket in one direction, there is an equal and opposite reaction, like the rocket moving in the other direction.
Find out more about Isaac Newton's Laws of Motion by clicking on the link below: