Momentum

Momentum

1/21/2021

Open Ended

Chop Wood Carry Water

Essential Question

What is impulse?

Objective

Students will be able to describe impulse using focused note taking and technology

Newton's Cradle

Open Ended

What happens if one ball is pulled from the Newton's cradle and released?

Open Ended

What happens if two balls are pulled from the same end and released?

Open Ended

3 balls?

Open Ended

How about one from each end at the same time?

There are multiple combinations but they all have to do with ....

MOMENTUM!

Impulse-Momentum Theory

• How many of you have been to a baseball game?

• Probably the most exciting play in baseball is the homerun.

• According to Newton's 2nd Law (F=ma), after the collision of the bat and the ball, the ball move away at a high velocity, and the bat continues along its path at a slower velocity

Impulse-Momentum Theorem

• This is all due to impulse

• The impulse on an object is the product of the average force on an object and the time interval over which it acts.

• Mathematically it looks like this...

• FΔt (the unit is Newton-seconds)

• With the baseball, it's a strong force over a very brief period.

Impulse-Momentum Theorem

• This leads us to momentum or the product of the object's mass and velocity

• Again, mathematically we see...

• p=mv (measured in kg-m/s)

Impulse-Momentum Theorem

• Impulse on an object is equal to the change in momentum, this is called the impulse-momentum theorem.

• It looks like this.

• FΔt=p_f-p_i

Open Ended

Example Problem - A 2200 kg vehicle traveling at 94 km/h (26 m/s) can be stopped in 21 s by gently applying the brakes. It can be stopped in 3.8 s if the driver slams on the brakes, or in 0.22s if it hits a concrete wall! (Ouch!). What is the impulse exerted on the vehicle and what is th average force exerted on the vehicle in each of these stops?

Practice Problems!

Have fun!!!

Open Ended

Exit Ticket - What is the formula for momentum?