Forces Affecting Motion

What is Motion? Motion is the change in position of an object. When an object is changing its position, it is in motion. It is displaying kinetic energy.

Newton’s Laws of Motion Newton’s 1st Law: An object at rest tends to stay at rest, and a an object in motion tends to stay in motion unless acted upon by an unbalanced force. Newton’s 2nd Law: An object will accelerate if the forces acting on it are unbalanced. Newton’s 3rd Law: For every action, there is an equal and opposite reaction.

What is Force? Force is a push or pull on an object. Balanced forces pull in opposite directions and cancel out one another. Unbalanced forces cause movement in the direction of the greatest push or pull. Some forces act when one object touches another. Other forces act over distance without objects touching.

What Forces Act on Objects? Gravity Friction Air Resistance or Drag

What is Gravity? A force of attraction, or pull, between any two objects Pulls together objects of all sizes without touching them The force that causes all objects to fall to the ground The force that keeps the planets and moons in orbit

Law of Universal Gravitation Sir Isaac Newton studied gravity. He said that gravity depends on the masses of the objects and the distance between them.

Gravity, Mass & Distance Gravity decreases as the mass of objects decreases. Gravity decreases as the distance increases between objects of equal mass.

What is Friction? A force that opposes the motion of one object moving past another Increases with the roughness of a surface Increases with weight Increases when surfaces press together with greater force Contact force – objects touch each other

What is Air Resistance? A force that opposes the motion of an object through the air Drags against a falling object and slows it down

What Affects Falling Objects? The mass or weight of an object does not affect the way it falls The shape of an object affects the way it falls. Broad, flat surfaces have the most drag. The greater the surface area, the greater the drag.

Let’s Review ________ is the change in position of an object. It is ____________ energy. __________ is a push or pull on an object. Newton’s 1st Law of Motion states that objects will not move or will keep moving unless acted upon by an _______________ ____________. ____________ is the force that causes objects to fall to Earth.

Who studied gravity? __________ If two objects have equal mass, the gravity between them will _______________ when the distance between them increases. __________ is a contact force that opposes motion and creates heat. ____________ opposes the motion of objects through air. __________ , not mass, affects how objects fall.

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