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Net Force . TEKS. ( 8.6) Science concepts. The student knows that there is a relationship between force and motion. The student is expected to: (A) demonstrate how unbalanced forces cause changes in the speed or direction of an object's motion. Forces.
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TEKS (8.6) Science concepts. The student knows that there is a relationship between force and motion. The student is expected to: (A) demonstrate how unbalanced forcescause changes in the speed or direction of an object's motion
Forces • Force : a push or pull that can change the motion of an object (measured in Newtons N) • Balanced force: Forces on an object that do not change the motion of the object • Unbalanced Force: Forces on an object that cause change in the motion of the object • Net Force: The total of all the forces acting on an object
Net Force ·If no forces act on an object, the net force on the object is zero ·Although this happens in physics problems, it is very unlikely in practice that an object will have no forces at all acting on it No forces acting… NF = 0
·If there is just one force on an object, then that force is the net force. In the diagram at left, the net force is 15 Newtons to the right. ·For example in free fall, the net force on an object equals its weight - the one force pulling on it. 15 N 15-0= 15 NF= 15 N to the right
·If 2 forces push or pull on an object in opposite directions, and the two forces cancel each other exactly, the net force is zero 25 N 25 N 25-25 = 0 NF = 0
·If two forces act on an object in opposite directions and they don't exactly cancel, what is left over is the net force (the difference in the forces). ·In the diagram below, the net force is 5 Newtons to the right. (in the direction of the bigger force) 10 N 15 N 15-10=5 NF = 5 N to the right
·If two(or more) forces act on an object in the same direction, the net force is the sum of the forces. ·In the diagram at left, the net force is 30 Newtons to the right. 10 N 20 N 10 + 20 = 30 NF = 30 N to the right
Quiz True or False The force that is “left over” after all of the forces acting on an object are cancelled and/or combined is called the net force.
A 3 N force and a 7 N force act in the same direction on a box. What is the magnitude of the net force on the box?
A 3 N force and a 7 N force act in opposite directions on a box. What is the magnitude of the net force on the box?