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Newton’s Laws. Physics 113 Goderya. Chapter(s): 5 Learning Outcomes: All. Force. Force: It is a push or a pull . Force has both magnitude and direction . Force exist in a variety of situations. Types of Forces.
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Newton’s Laws Physics 113 Goderya Chapter(s): 5 Learning Outcomes: All
Force • Force: It is a push or a pull. • Force has both magnitude and direction. • Force exist in a variety of situations.
Types of Forces • Contact Forces: Force is due to physical contact between the bodies. Example mechanical forces. • Field Force: No physical contact is necessary to experience the force. Examples are Gravitational, Electrical, Magnetic, and Nuclear Forces.
A New Era of Science Mathematics as a tool for understanding physics
Isaac Newton (1643 - 1727) • Building on the results of Galileo and Kepler • Adding physics interpretations to the mathematical descriptions of astronomy by Copernicus, Galileo and Kepler Major achievements: • Invented Calculus as a necessary tool to solve mathematical problems related to motion • Discovered the three laws of motion • Discovered the universal law of mutual gravitation
A New Era of Science Mathematics as a tool for understanding physics
Isaac Newton (1643 - 1727) • Building on the results of Galileo and Kepler • Adding physics interpretations to the mathematical descriptions of astronomy by Copernicus, Galileo and Kepler Major achievements: • Invented Calculus as a necessary tool to solve mathematical problems related to motion • Discovered the three laws of motion • Discovered the universal law of mutual gravitation
Newton’s Laws of Motion (1) • A body continues at rest or in uniform motion in a straight line unless acted upon by some net force. An astronaut floating in space will continue to float forever in a straight line unless some external force is accelerating him/her.
Newton’s Laws of Motion (2) • The accelerationa of a body is inversely proportional to its mass m, directly proportional to the net forceF, and in the same direction as the net force. a = F/m F = m a
Newton’s Laws of Motion (3) • To every action, there is an equal and opposite reaction. M = 70 kg V = ? The same force that is accelerating the boy forward, is accelerating the skateboard backward. m = 1 kg v = 7 m/s
The Universal Law of Gravity • Any two bodies are attracting each other through gravitation, with a force proportional to the product of their masses and inversely proportional to the square of their distance: Mm F = - G r2 (G is the Universal constant of gravity.)
Gravity and Distance: The Inverse-Square Law Inverse-square law • relates the intensity of an effect to the inverse- square of the distance from the cause • in equation form: intensity = 1/distance2 • for increases in distance, there are decreases in force • even at great distances, force approaches but never reaches zero
Universal Gravitation Universal gravitation • everything attracts everything else example: Earth is round because of gravitation—all parts of Earth have been pulled in, making the surface equidistant from the center • The universe is expanding and accelerating outward.