Force: Identify Various Kinds Of Forces And Their Influences On An Object

Force Objectives: identify various kinds of forces and their influences on an object Student’s task: 1. To investigate friction forces on various kinds of surfaces. 2. To show some examples of friction forces that are advan tageous or disadvantageous.

1 donkey

What is the meaning of Force? Force is pull or push given to an object by another object. Force

Touch Force

Non-Touch Force

Force is a quantity which is measured using the standard metric unit known as the Newton. A Newton is abbreviated by a "N."

Touch Forces Frictional Force Tension Force Normal Force Air Resistance Force Applied Force Spring Force

Non Touch Forces Gravitational Force Electrical Force Magnetic Force

Drawing Force Force is drawn as an arrow.

The length of the arrow indicates the quantity of a force and the direction of the arrow indicates the direction of the force.

Adding Force 1.

2.

If two forces working in the same direction, the resultant force is obtained by totaling the two force. If two forces have opposite directions, the resultant force is subtracting the smaller one from the bigger one with direction following the biger force.

Example Draw 2 forces in the same direction as F1 = 20 N and F2 = 50 N at the scale of 10 N = 1 cm. Draw 2 forces in the opposite direction as F1 = 20 N and F2 = 50 N at the scale of 10 N = 1 cm. Calculate and Draw a resultant force from F1 and F2

Friction

2 touching surfaces are magnified. The quantity of the friction depends on the roughness of the surfaces.

Friction  Force

that slows down motion.  The Force is friction.  Friction is a force to oppose motion between two touching surfaces.

Examples and Quantity of Friction

Quantity of friction force depend on: • Roughness of two surfaces. 2. Force pressing two touching surfaces together.

The kinds of Friction Forces 1. Static friction force fs

F < fs

F

F fmax

F = fmax

Stop

Start to move

2. Kinetic friction force

fk

F

F > fk

Move

Advantages and Disadvantages of Friction

dvantage: 1. We walk on the floor 2. We grip an object.

Disadvantage: 1. Friction between the chain and the gear in a bike cycle causes them to become worn out. 2. Friction among the machine’s components in the vehicle causes the heat.

Conclusion Force is pull or push given to an object by another object. Force is drawn as an arrow.

Conclusion 1. Friction is a force to oppose motion between two touching surfaces. 2. There are have two kinds of the friction force; the static friction and the kinetic friction. 3. The friction of force have of the advantages or the disadvantages.