# FORCES IN EQULIBRIUM

### Statics and Newton’s First Law of Motion

## Vocabulary words

component:* *the projection of a vector quantity, as force or velocity, along an axis.

equilibrium: a state in which opposing forces or influences are balanced.

free-body diagram

forces

applied: **force** that is **applied** to an object by a person or another object. PUSH OR PULL

elastic: able to resume its normal shape spontaneously after contraction, dilatation, or distortion.

electrostatic: Charge induction occurs when a negatively charged object repels (the negatively charged) electrons from the surface of a second object.

friction:the resistance that one surface or object encounters when moving over another.

gravitational:** force** that attracts any object with mass.

net:overall **force **acting on an object.

normal:the component, perpendicular to the surface (surface being a plane) of contact, of the contact **force** exerted on an object

tension:the **force** that is transmitted through a string, rope, cable or wire when it is pulled tight by **forces**acting from opposite ends.

nuclear: strong attractive force between nucleons in the atomic nucleus that holds the nucleus together.

inertia:a tendency to do nothing or to remain unchanged

system:a set of connected things or parts forming a complex whole, in particular.

## Formulas / Units / Symbols

__Formulas / Units / Symbols__

SOH-CAH-TOA

Answer:

sin θ = 3/5 = 0.6

cosθ = 4/5 = 0.8

tanθ = 3/4 = 0.7

Fnet = F1 + F2 … +Fn

Adding up all the forces that are present:

600N+(-500G)=100net

F2 = Fx2 + Fy2

Newtons(N)

1 N = 1 kg * 1 m/s2

ex. (12.6kg)(9.8m/s^2)=123.5N

## Main Ideas

3-1. I can describe the ideal

conditions applied to the study of forces (ignoring friction).

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3-2. I can diagram and calculate the horizontal and vertical components of force.

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3-3. I can explain contact forces on the atomic scale using the particle model.

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3-4. I can mathematically describe frictional forces.

3-5. I can explain and calculate the apparent weight of an object when it’s acceleration is zero.

3-6. I can apply Newton’s first law of motion to mathematically describe and predict the effects of forces on complex systems of objects.