Physics Spring 2015. Go Over Friction Quest ◦ Take the Friction Quest if missing yesterday Second Semester Review Assignment Notes: Work.

Physics Spring 2015

Go Over Friction Quest ◦ Take the Friction Quest if missing yesterday

Second Semester Review Assignment

Notes: Work

Review Mid-Semester Review◦ Collect Review

Notes: Work and Power

Practice: Work and Power

HW: Complete the Work and Power Assignment

Which of these would you classify as doing work?

◦ Lifting weights◦ Climbing stairs◦ Moving a couch◦ Trying to push a car that is stuck◦ Carrying you backpack around school

Work is the application of any force over a distance.

The equation for work is…Work = Force x distance

◦ If there is an applied force, but no movement is working being done?

Which requires more work, to move 10 2N books 10m one at a time, or move all of the books at once?

How did we measure power in the circuits unit?

What did we say that the electricity company sells us actually?

Power is still the rate of energy used per time

In this unit:◦ Power = Work (J) / time (sec)◦ Units: Watts

A person expends 500J of energy while climbing a flight of stairs. If it takes this person 15 seconds to climb this flight, how much power did this person use?

If a car uses 100,000J of energy over the course of a 120 second drive. What is the power used?

If one horse can expend 30 Watts of power, how much horsepower was this car using?

Review Work Assignment

Horsepower Lab

Burning Calories Analysis and Conclusion of lab

HW: Complete Lab if not done in class

The energy of position or height

This tells us how much work an object could do.

GPE = mass * acceleration of gravity * height

The energy of movement

The amount of energy a moving object has.

KE = ½ mass * velocity2

Energy can never be created nor destroyed it just changes forms, from GPE to KE.

As GPE decreases, the amount of KE increases.

As KE decreases, the amount of GPE decreases.

Horsepower Lab

PE v. KE note review

Practice Problems: PE v. KE

Energy Skate Park

HW: PE v. KE assignment

What is the kinetic energy of a fastball (.149kg) traveling at 26.6 m/s?

How much potential energy does a ball have that is held motionless at a distance of 100m if the ball has a mass of 2kg.

Energy Note Check

Work and Energy Practice

LOCOE Exit Slip

HW: None

Go Over exit slip procedures

Notes: Conservation of energy◦ Resubmit Exit slip from yesterday

Bowling Ball Demo◦ Chromebook research

Bowling Ball Explanation Activity

Energy is NEVER created or destroyed. It is only transformed into a different form of energy.

When an object is at rest above the ground contains 100% potential energy.

An object moving very close to the ground (height = 0m) it contains 100% KE

100% KE

100% GPE

If a basketball is dropped from a height of 1m, how fast will it be moving when it hits the ground? The basketball has a mass of .3kg.

GPE (before dropped) = mgh = .3kg * 10m/s2 * 1m3 J

GPE at top = KE at bottom (Conservation of Energy)

KE (at bottom) = ½mv2 => ½ *.3kg * v2

v = .39 m/s

Review Bowling Ball Lab

Rollercoaster Problem◦ Conservation of Energy

Before tomorrow Quiz on LOCOE

HW: None, unless you need practice

Finish Quiz/Rollercoaster Problem

Work and finish Spring Energy Lab

Happy Prom Weekend!!

HW: None

Let me see you all on Monday!