Motion Objectives: Displacement, velocity, acceleration Motion with Constant Acceleration Free Fall

Distance and Displacement Q1. The width of a room is 7 m (approx. 7 yards). You walk from one wall to the other wall, what is the total: Distance Displacement

Distance and Displacement Q1. The width of a room is 7 m (approx. 7 yards). You walk from one wall to the other wall, what is the total: Distance: 7 m Displacement: 7 m Q2. Now, you walk back to the wall where you started originally. What is the total: Distance: Displacement:

Distance and Displacement The length of the path traveled Displacement The CHANGE in the position

Distance and Displacement The length of the path traveled Displacement The CHANGE in the position Q3. You dive in the swimming pool and begin to do laps. The swimming pool is 25 m long. After 2 complete laps, what is the distance traveled? (a) 0 (b) 50 (c) 100 (d) Cannot tell

Distance and Displacement The length of the path traveled Displacement The CHANGE in the position Q3. You dive in the swimming pool and begin to do laps. The swimming pool is 25 m long. After 2 complete laps, what is the distance traveled? (a) 0 (b) 50 (c) 100 (d) Cannot tell Q4. What is your total displacement? (a) 0 (b) 50 (c) 100 (d) Cannot tell

Velocity and Speed displacement distance traveled = time it took speed change in position = time it took velocity number number + direction

Velocity and Speed Speed or velocity? displacement distance traveled = time it took speed change in position = time it took velocity number number + direction Speed or velocity? You are driving your car at 65 mph. You are lost and call a friend to tell him you are driving north at 45 mph You tune in to the Weather channel and they report north-west winds at 50 mph

Velocity and Speed displacement distance traveled = time it took speed change in position = time it took velocity number number + direction Q5. The width of a room is 7 m (approx. 7 yards). You walk from one wall to the other wall and back in 10 s. What was your speed? And your velocity?

Velocity and Speed displacement distance traveled = time it took speed change in position = time it took velocity number number + direction Q5. The width of a room is 7 m (approx. 7 yards). You walk from one wall to the other wall and back in 10 s. What was your speed? And your velocity? distance traveled = time it took speed displacement = time it took velocity speed = ? velocity = ?

Acceleration displacement average distance traveled = time it took speed average change in position = time it took velocity average change in velocity = time it took acceleration https://answers.yahoo.com/question/index?qid=20080109200232AAmZiYr

Acceleration displacement average distance traveled = time it took speed average change in position = time it took velocity average change in velocity = time it took acceleration Q6. Claims on the web state that a NASCAR Cup car can run 0 – 60 in 3.0 s. What is its average acceleration? https://answers.yahoo.com/question/index?qid=20080109200232AAmZiYr ? average change in velocity = time it took acceleration Ans. ?

Displacement, Velocity, Acceleration 20 P1. Your speedometer reads 50 mph. Is this average speed or instantaneous? Answer: P2. You are driving at 35 mph. What Is that in m/s? Answer: P3. A car accelerates from 60 ft/s to 70 ft/s. What Is its average acceleration? What is the acceleration in m/s? Answer: P4. A pick up truck pulling a trailer accelerates at 3.25 m/s2 for 5.80 s. If it starts from rest, what is its final velocity? Answer:

Average vs. Instantaneous Q7. How can we calculate the speed or velocity at one instant? acceleration = constant velocity = Beginning velocity + acceleration x time elapsed position = beginning position We’ll simplify this and use it for free fall. + beginning velocity x time elapsed 2 + 0.5 acceleration x time elapsed

Free Fall Q8. Which one will hit the ground first? (a) Ball (b) Paper (c) Both (d) Cannot tell Class demo . Do paper and ball. Clicker question to see what they think.

Free Fall Galileo (1589): 186 ft 1 s: 16 ft 2 s: 64 ft 3 s: 144 ft Galileo’s Experiment

Free Fall Galileo (1589): 186 ft Pattern 1 s: 16 ft 1 2 s: 64 ft 4 Galileo’s Experiment : The Pattern of distance ~ (t)^2 4 s: ?? ft ??

Free Fall Apollo 15 Moon Experiment: Pattern 1 s: 16 ft 1 2 s: 64 ft 4 9 144 ft Apollo 15 Experiment on the Moon Apollo 15 Moon Experment with a Hammer and a Feather

Free Fall: Example Q9. The acceleration due to Earth’s Gravity is 9.8 m/s2. What is that in ft/s2? Answer: Fill in the numbers and calculate

Free Fall: Example 10 min Q10. If you drop a rock from the top of a building and it hits the ground 1.5 s later, how tall is the building in ft? acceleration = 32.152 ft /s2 velocity = Beginning velocity + 32.152 ft /s2 x time elapsed Fill in the numbers and calculate position = beginning position + beginning velocity x time elapsed 2 + (0.5) 32.152 ft /s2 x time elapsed

Free Fall Problems DIY P1. Your speedometer reads 50 mph. Is this average speed or instantaneous? Answer: P2. You are driving at 35 mph. What Is that in m/s? Answer: P3. A car accelerates from 60 ft/s to 70 ft/s. What Is its average acceleration? What is the acceleration in m/s? Answer: P4. A pick up truck pulling a trailer accelerates at 3.25 m/s2 for 5.80 s. If it starts from rest, what is its final velocity? Answer:

Constant Acceleration Problems DIY P1. You drop a rock from a bridge. It hits the water in 3.0 s. How far below is the surface of the water? Answer: = position + (0.5) 32.152 ft /s2 2 x Fill in the numbers and calculate P2. What will be the speed of a rock 1.5 seconds after it has been dropped? Answer: = velocity + x 32.152 ft /s2