a. Apply Newton's Third law to design a solution to problem involving the motion of two colliding objects.
Motion
Motion is the change of position overtime. In order to know how quickly an object change its position, measuring speed is needed.
Example - If a ball is being kicked and moved with a speed of 10 m/s, the ball is in motion. After 1 second, the ball move 10 meter away from the starting position. That is, the ball has changed position. |
Force
Force is a push or a pull. To change the motion of an object, an unbalanced force is needed. Forces varies in type, some example of forces include contact force, gravity or friction,... The standard unit for force is Newton (N), and one Newton is defined as the amount of force needed to make 1 kilogram of mass accelerate by 1 meter per second per second (1 m/s/s).
Example - When a person pushes the chair towards a particular position, that person is exerting a force on the chair. While pushing the chair, a backward force on chair is formed created called friction. Friction is a force between 2 surfaces. |
Newton's third law of Motion
Newton's third law of Motion states that every time one object exerts a force on another object, the second object exerts a force that is equal in size and opposite in direction back on the first object. The initial force that is exerted by the first object is called the action force, and the force that the second object exerted back is called reaction force.
Example - When a person dropped a tennis ball on the ground, the force of gravity acted on the ball pull the ball downward. The force that the tennis ball exerted by gravity on the ground is enacted in the opposite direction by the ground, making the tennis ball bounced back. |
b. Provide evidence that the change in an object's motion depends on the sum of the forces on the object and mass of the object.
Net force
Net force is over all force that is acting on an object in a specific direction. For an object to change in motion, an unbalanced force is needed. An unbalanced force is where the net force on an object is greater than 0 N.
Example - If a force of on the left side of a box is 3 N, and the opposing force on the right side is 5 N, the net force that is acting on that object is 2 N, towards left, and that is an unbalanced force. |
Mass and gravity, and friction
Mass is the measure of how much an object has. With more mass, the more force gravity create. Gravity is the force of attraction between 2 mass. And with more force, the object is being pulled down more, pressing against the surface, creating more friction. Friction is an opposing force between 2 surfaces. And with more friction pushing against the object, the harder it is to move it.
Example - If a box is being pulled by gravity with a force of 7 N, pushing it will be easier than when it has more mass and gravity causes a stronger force, since the friction between the box and the table will be less than when it has more mass. |