Warm Up

What is the tension in a 2.75 m cord that whirls a 5.6 kg object in a circular path at a speed of 4.83 m/s?

Warm Up

What is the tension in a 2.75 m cord that whirls a 5.6 kg object in a circular path at a speed of 4.83 m/s?

F = mv2 = (5.6 kg)(4.83m/s)2 = 47.5 N r 2.75 m

Physics Ch. 10 Center of Gravity

Start with a silly activity….

What happens when you try to touch your toes and have your back and heels against a wall??

Center of Gravity• The average position of weight.

Center of Mass• Average position of matter.

If you attempt to balance an L shaped object on its small end,

what would happen? Why?

If you attempt to balance an L shaped object on its small end,

what would happen? Why?

It would fall. Why? Because it was not supported at its average position of weight (CofG)

Stability

Stable Unstable NeutralEquilibrium Equilibrium Equilibrium

Stability

Stable Unstable NeutralEquilibrium Equilibrium Equilibrium

Work must be done to raise CofG

Stability

Stable Unstable NeutralEquilibrium Equilibrium Equilibrium

Work must be CofG is lowered withdone to raise CofG any displacement

Stability

Stable Unstable NeutralEquilibrium Equilibrium Equilibrium

Work must be CofG is lowered with Displacement will done to raise CofG any displacement neither raise nor

lower CofG

• Which block requires more work to tip over? Why?

I need a volunteer

• Sit in a chair at the front of class. • Attempt to stand up without putting your feet

under your chair(Your feet need to be out in front of you chair)

What happens? Why?

Center of gravity in organisms with limbs is not located in a fixed

position!

It depends on orientation!

Next

Now its time for Myth Busters: Circular Motion!!!