EXS 375 Chapter Notes - Chapter 6: Ground Reaction Force, Normal Force, Net Force
17 Sep 2016
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When left alone the momentum of a system does not change. Newton"s first law- a body will remain at rest or continue to move with a constant speed in a straight line unless acted upon by an outside force. System- the thing that you are studying. Internal forces- any forces inside the body that help hold it together. They cannot change the momentum of a system. External forces are outside the body and will change the momentum of the system. Larger acceleration decrease mass or increase force. Acceleration will always be in the direction of the force, but the acceleration is not always the direction the body is moving. Force is not always in the direction of motion; negative force in a negative direction causes body to speed up. Propulsive forces: a force that is causing the body to speed up: if the direction is positive, it will be positive, if the direction is negative it will be negative.
