PHY131H1S - Class 7 Today: Review for tomorrow’s test In tba, 6:00 – 7:30pm On Chapters 1-3, Error Analysis Mini-Document, and Sections 4.1 through 4.4. Bring a calculator and one 8.5x11’ aid sheet which you prepare, double-sided

You drop a glass barometer from the top of McLennan Physical Labs. A short time later, before the barometer hits the ground, you drop a bottle of scotch. As they fall, the distance between the barometer and bottle A.decreases B.increases C.stays the same. Niels Bohr

Relative Motion Example 1: A passenger walks toward the front of the train at 5 m/s. The train is moving at 36 m/s. What is the speed of the passenger relative to the ground? Example 2: Car A is traveling at 25.0 m/s E toward Bloor and Keele. Car B is traveling at 15.8 m/s N toward Bloor and Keele. Just before they collide, what is the velocity of car A relative to car B?

A particle moves from position 1 to position 2 during the interval ∆t. Which vector shows the particle’s average velocity?

A. 0–1 s B. 1–2 s C. 2–3 s D. 3–4 s During which time interval is the particle described by these position graphs at rest?

A. less than 2 m from the base. B. 2 m from the base. C. greater than 2 m from the base. A 50 g ball rolls off a table and lands 2 m from the base of the table. A 100 g ball rolls off the same table with the same speed. It lands at a distance

The Gaussian: 68% of data between the dotted lines on the graph.

Mean and Standard Deviation of a set of numbers Repeat the same measurement N times. You measure the values x 1, x 2, x 3, …, x N. In other words, you measure x i, where i is an index which ranges from 1 up to N. The estimated mean is The estimated standard deviation is You can estimate that σ is the error in any individual measurement x i : Δx i = σ.

Propagation of Errors z = A x Δz = A Δx

Repeated Measurements Repeated n times Each individual measurement has an error of precision  x

Does not contain s i or s f ! Does not contain  t ! Does not contain v fs ! Motion with Constant Acceleration: another useful equation! Does not contain a s ! (..but it does require that a s is a constant.) This is just the average speed.

Projectile Motion Example A car drives off a cliff of height d with speed v 0. The ground is horizontal both at the top and bottom of the cliff. How far from the base of the cliff does the car land?

Before Class 8 on Wednesday Test is tomorrow! tba, 6:00pm. On Chs. 1-3, Error Analysis, and Sections 4.1 through 4.4. Bring a calculator and one 8.5x11’ aid sheet which you prepare, double-sided By Wednesday, please finish reading Chapter 4 Something to think about: You are driving North Highway 427, on the smoothly curving part that will join to the Westbound 401. Your speedometer is constant at 115 km/hr. Your steering wheel is not rotating, but it is turned to the left to follow the curve of the highway. Are you accelerating? If so, in what direction?