Force and Newton's Laws

FORCES:
(Newton's Laws)

Background research on what forces are, Newton's 3 Laws, and how to calculate the different forces that act on an object!

​A force is a PUSH or PULL on an object.

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What is a Force?

An object in motion will stay in motion and an object at rest will stay at rest unless acted upon by an outside force.

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Newton's 1st Law

An object will accelerate in the direction of Net Force.

Often shown as........

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Newton's 2nd Law

Write what is given for info in the problem.

​​Given?

​Write what the problem is asking you to solve.

Asked For?

​Write the formula that has the givens and what is being asked for in it.

Formula?

​Plug in the givens and use Algebra (PEMDAS) to solve. Re-write after every reduction to organize.

Plug and Solve

​Newton's 2nd Law Math

Fill in the Blanks

An object with a mass of 5.0 kg accelerates 8.0 m/s2 when an unknown force is applied to it. What is the amount of the force?

Fill in the Blanks

An object accelerates 3.0 m/s2 when a force of 6.0 newtons is applied to it. What is the mass of the object?

Fill in the Blanks

An object with a mass of 3.0 kg has a force of 9.0 newtons applied to it. What is the resulting acceleration of the object?

​There are MANY different types of Forces that can affect an object and its motion!

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Types of Forces?

Multiple Choice

Force that pulls an object towards the center of the Earth?

• Gravitational Force

• Tensional Force

• Friction Force

• Applied Force

• Normal Force

Multiple Choice

Force that acts in the opposite direction of gravity so things can stay where they are and not fall forever?

• Gravitational Force

• Tensional Force

• Friction Force

• Applied Force

• Normal Force

Multiple Choice

Force that pulls equally in opposite directions?

• Gravitational Force

• Tensional Force

• Friction Force

• Applied Force

• Normal Force

Multiple Choice

Force that act is in the opposite direction of motion?

• Gravitational Force

• Tensional Force

• Friction Force

• Applied Force

• Normal Force

SURE!!! We represent this with a Free Body Diagram!!
FBD for short.......

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Can more than 1 Force act on an object?

Here is an example of what a FBD problem looks like. Solving them is like solving a logic puzzle!

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Example FBD Problem:

​WHAT DOES IT ALL MEAN!!!!!!

MORE FORCE FORMULAS!!

​Strategy:

​- Solve got Fg or m first depending on what's given.
- Solve for Fn next because it's easiest.
- Solve for Ff or Fnet depending on what's given.
- Solve for what's left.

What it looks like solved:

​WAIT A MINUTE!!!
- NEGATIVE FORCE?
- The (-) sign in Force just means DIRECTION!
(-) is left or down
(+) is right or up

So the formula to see how much something weighs is W = m * g

Fg is also known as WEIGHT

​MASS = how much MATTER is in you.

​WEIGHT = the force of GRAVITY on you.

For every action Force there is an equal in size but opposite direction reaction Force.

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Newton's 3rd Law

Multiple Choice

What is the ACTION force when a Rocket is flying through the sky?

• Rocket pushing exhaust out.

• The exhaust pushing against the rocket.

Multiple Choice

What is the REACTION force when you jump into a pool?

• Person pushing against the pool.

• The pool pushing against the person.