Measurements Lab Requirements pt 1 What you should have finished in lab on Wednesday: (if you need more time, let me know ASAP) 1.Measure inside & outside diameters of graduated cylinder. 2.Measured mass of metal cylinder 3.Measured diameter of metal cylinder using micrometer 4.Measured height of metal cylinder using Vernier Caliper 5.Measured your knuckle width with Vernier Caliper & told me the value

Measurements Lab Requirements pt 2 What you should calculate: (show all work, preferably on another paper, if you want me to find your mistakes) 1.All values should have: value ± abs error units (% error) 2.Top box: row 3 should have 2 values: a subtraction (and errors), and a division (and errors). Follow rules for errors. 3.Bottom box: Calculate radius, area, volume, and density from the measurements. Each value should have absolute & percent errors and units calculated. Remember  water = 1 g/cm 3 for comparison. 4.(continued)

Measurements Lab Requirements pt 3 What you should calculate: 4.When ABSOLUTE errors are MEASURED, they should have 1 significant figure. The size of the absolute error is based on how well you think the tool works or how well you used it. 5.When ANY error is CALCULATED, use two significant figures. 6.Calculate the class average knuckle width, the standard deviation of the data, how many data values fit inside the 1  and 2  ranges, which range your knuckle is in, and answer the question at the bottom of the page. Download data from web page.

Graphs Review rules for x-t & v-t graph Show an accelerating object on v-t graph –Clicker question (next slide) Show rules for v-t & a-t graph [negative area!] Average velocity equation For constant acceleration only: Acceleration equation Area under v-t graph equation Other equations of motion

At the end of the v-t graph shown, what is the velocity? 1.Positive (which means moving which way) 2.Negative (which means moving which way) 3.It is stopped

At the end of the a-t graph shown, what is the acceleration? 1.Positive 2.Negative 3.Zero

Acceleration graphs Do quick quiz 2.3 (page 32) with clickers. (next few slides) Do quick quiz 2.4 (page 34) with clicker (slide after)

Refer to page 32, figure Top row = v-t graphs. Bottom Row = a-t graphs. Which in bottom matches with “a”? 1.Don’t pick 2.Don’t pick 3.Don’t pick 4.D 5.E 6.F

Refer to page 32, figure Top row = v-t graphs. Bottom Row = a-t graphs. Which in bottom matches with “c”? 1.Don’t pick 2.Don’t pick 3.Don’t pick 4.D 5.E 6.F

Refer to page 32, figure Top row = v-t graphs. Bottom Row = a-t graphs. Which in bottom matches with “b”? 1.Don’t pick 2.Don’t pick 3.Don’t pick 4.D 5.E 6.F

Refer to page 34, figure Which graph is physically impossible? Select all that apply. 1.A 2.B 3.C

After working on the handout’s first column Gravity = constant downwards acceleration. Rate = 9.8 m/s per second (9.8 m/s/s) [Trivia: 32 ft/s/s] One more clicker question related to “harder” problem. Quick Quizzes 2.6, 2.7 with clickers (coming in a few slides). Quick Quiz 2.8 is a good question to help you understand acceleration.

An object is tossed upwards into the air. On the way up, what is the velocity? 1.Upwards (+) 2.Downwards (-) 3.Zero

An object is tossed upwards into the air. On the way down, what is the velocity? 1.Upwards (+) 2.Downwards (-) 3.Zero

An object is tossed upwards into the air. At the top, what is the velocity? 1.Upwards (+) 2.Downwards (-) 3.Zero

An object is tossed upwards into the air. On the way up, what is the acceleration? 1.Upwards (+) 2.Downwards (-) 3.Zero

An object is tossed upwards into the air. On the way down, what is the acceleration? 1.Upwards (+) 2.Downwards (-) 3.Zero

An object is tossed upwards into the air. At the top, what is the acceleration? 1.Upwards (+) 2.Downwards (-) 3.Zero

A tennis player on serve tosses a ball straight up. While the ball is in free fall, does its acceleration: 1.Increase the whole time 2.Decrease the whole time 3.Increase then decrease 4.Decrease then increase 5.Remain constant

As the tennis ball travels through the air, its speed: 1.Increases the whole time 2.Decreases the whole time 3.Decrease then increase 4.Increase then decrease 5.Remain constant

Do first falling from tall building question on handout Then ask the next clicker question

Will the speed when it hits the ground be … than m/s (when dropped) 1.Faster 2.Slower 3.Same speed

Two objects are tossed. One is tossed upwards +10 m/s. One is tossed downwards -10 m/s. Which is moving fastest when it hits the ground? 1.Upwards tossed object 2.Downwards tossed object 3.Both moving same speed 4.Not enough information given

The instant before the ball lands on the elevator, which is moving faster? 1.Ball 2.Elevator 3.Same

Which is the same for the ball & elevator when the ball lands on elevator? 1.Position 2.Velocity 3.Acceleration

What’s the elevator’s acceleration? 1.-6 m/s 2.0 m/s/s m/s/s