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Forces & Friction. Chapter 10.1 and 10.2. FORCE & NET FORCE. FORCE is a push or pull on an object Described by the magnitude and direction in which it acts. SI Unit = Newton NET FORCE is the total/cumulative force on an object (add the two forces). Unbalanced & Balanced Forces.
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Forces & Friction Chapter 10.1 and 10.2
FORCE & NET FORCE • FORCE is a push or pull on an object Described by the magnitude and direction in which it acts. SI Unit = Newton • NET FORCE is the total/cumulative force on an object (add the two forces)
Unbalanced & Balanced Forces • Unbalanced Force: Causes an object to stop moving or change direction. Result in a net force and cause a change in the object’s velocity (motion) • Balanced Force: Forces in equal magnitude & opposite direction. No movement / No change in velocity
What is the Net Force for the red airplane? Why are these examples of unbalanced forces? What is the Net Force for the green speed racer?
BRAIN BREAK! With your partner, discuss how balanced and unbalanced forces can apply to an arm wrestling match.
FRICTION • FRICTION is a force that two surfaces exert on each other when they rub against each other Forces act in OPPOSITE directions to each other! The strength of friction depends on 1) the type of surface 2) how hard the surfaces push each other.
Types of Friction 1) Static Friction (Strongest) Acts on objects that are not moving. Works in opposite direction to intended motion. 2) Sliding Friction Occurs when two solid surfaces slide over each other. 3) Rolling Friction Occurs when an object rolls over a surface. Works in direction opposite to intended motion. 4) Fluid Friction (Weakest) Occurs when a solid object moves through a fluid (water, air, oil)
Which skater will experience the most friction? Hint: Who exerts more downward force?