Welcome Physicists! DQ: Draw a free body diagram for an airplane flying (assume the plane is climbing and speeding up - include air resistance) Today: Go over homework Balanced vs. Unbalanced forces Measuring Motion Homework: Apple on a Desk

Forces, Balanced and Unbalanced What is happening if an object’s motion is changing? How do you make something change its motion? If something’s motion isn’t changing, what does that mean? – Book sitting on a table – A ball rolling at a constant speed (not speeding up or slowing down) – A balanced teeter-totter

If an object’s motion isn’t changing (not speeding up or slowing down or changing direction) then we know the forces are balanced If we added them all together, they would equal zero F g down + F N up = 0

Other Examples

But if we increase the force on one side by say, adding mass Now the forces are unbalanced so the motion changes MotionMotion

Think-Write-Pair-Share What about with the rocket launch? What are the forces involved in launching the rocket? – Draw the launcher in your journal again, but this time, diagram the forces involved – Discuss your drawing with your table mates

Watch the rocket launch again How many ways can we describe or measure the motion of the rocket? Pathway Different portions of flight – Before launch – From the bottom to the top of the launch tube – From the top of the launch tube to the top of the flight – From the top of the flight to the ground Maximum height Flight time Velocity Acceleration

Some (more) definitions Speed = distance/time Velocity = distance/time and includes a direction Acceleration is the change in velocity over time or the rate of change of velocity – Is an object increasing velocity? Positive acceleration – Is an object decreasing velocity? Negative acceleration

Exit Ticket Define energy Define force Describe the relationship between energy and force HOMEWORK Apple on a Desk – Use complete sentences to answer and include scientific vocabulary we have learned in your answer. Use the back of the paper if you need more room! DUE NEXT CLASS Some possible vocabulary words to use: Force Gravitational force Frictional force Applied Force Normal Force