Warm-Up: October 30, 2015 A 15.0 kg box is sitting at rest on a ramp. The ramp is offset 15.0° from horizontal. a)Draw a free body or force diagram for

Warm-Up: October 30, 2015

• A 15.0 kg box is sitting at rest on a ramp. The ramp is offset 15.0° from horizontal.

a) Draw a free body or force diagram for the box.

b) Calculate the magnitude of each force acting on the box.

• A crate weighing 9.80x103 N is pulled up a 37.0° incline by a force parallel to the plane. If the coefficient of kinetic friction between the crate and the surface of the plane is 0.750, what is the magnitude of the applied force required to move the crate at a constant velocity?

Warm-Up: November 2, 2015


1.18x104 N

Force and Motion in Two Dimensions

Section 5.3

• A packing crate is placed on a 20.0° inclined plane. If the coefficient of static friction between the crate and the plane is 0.650, will the crate slide down the plane? Justify your answer.

You-Try #1

You-Try #1

• A 5.0 kg wooden block is placed on an adjustable wooden inclined plane. ,

a) What is the angle of incline above which the block will start to slide down the plane?

b) At what angle of incline will the block then slide down the plane at constant speed?


Warm-Up

• Zgorb lives on a planet where the acceleration due to gravity is 8.50 m/s2. Zgorb places a 12.0 kg box on a ramp that is 20.0° off of horizontal. The coefficient of static friction between the box and the ramp is 0.400, while the coefficient of kinetic friction is 0.250. Assume air resistance is negligible.

• Describe the motion of the box.

You-Try #3

You-Try #3

• A 175 kg crate on a horizontal floor is being pulled by a rope pulling with a force 10° above horizontal. ,

a) How hard does the rope have to pull in order to get the box to start moving?

b) How hard does the rope have to pull in order to keep the box moving at a constant speed?

You-Try #4

You-Try #4

Assignment

• Read Section 5.3• Page 133 #33-37• Page 135 #38-41

• A block of wood is on a wooden ramp that is 30.0° away from horizontal. The block is pulled up the ramp at a constant 1.00 m/s by a rope that is parallel to the wooden ramp. The tension in the rope is 25.0 N. The coefficient of kinetic friction is 0.400.

• Is it possible to determine the mass of the block?

• If so, what is it? • If not, why not?

Warm-Up: November 4/5, 2015

Warm-Up

• A 175 kg crate on a horizontal floor is being pulled by a rope pulling with a force 10° above horizontal. ,

a) How hard does the rope have to pull in order to get the box to start moving?

b) How hard does the rope have to pull in order to keep the box moving at a constant speed?

You-Try #4

You-Try #4

Lab• Work with your assigned group to:a) Determine the coefficient of static friction

between a physics textbook and a calculator.b) Determine the coefficient of kinetic friction

between a physics textbook and either a horizontal table top or the floor.

• Allowed materials: rulers, meter sticks, stopwatch (on phone), textbook, calculator

• After finishing, make a poster to present your procedures and conclusions.

Lab Roles• Leader – Collect and return supplies, keep

group on task, assist group members, fill in for absent group members.

• Procedure recorder – Write down everything that the group does to accomplish the objective of the lab.

• Data/calculations recorder – Write down all of the data that the lab group gathers and all calculations done by the lab group.

• Presenter – Present procedures and results to the class.

Lab Groups – Period 2Group # Leader Pro. Rec. Data Rec. Presenter

1Nagelvoort, Christopher O, Christina Sharma, Amitesh

Padmanaban, Sneha

2Obermiller,

Andrew Bathard, Hallee Gupta, Mihir Clark, Nina

3 Waldman, PhilipCastaneda,

Ernesto Rao, Ananya Thomas, Zoe

4 Lodge, Grace Imler, Carson Bhushan, Somil Lee, Rudolph

5 Yang, Jerry Nguyen, Wendy Hardisty, Sabrina Sandfer, Connor

6 Kapoor, Pia Folkl, Julia Kwan, Crystal Hagstrom, Erik

7 Nguyen, HaleyLaudenslager,

Alexis Jones, Cameron Wedge, Lauren

8 Andersen, Blake Brana, Jennifer Andersen, Blake Kye, Johanna

9 Calkins, Nicholas Pennington, Julia Calkins, Nicholas Almond, Amber

• A hockey puck is sliding across horizontal frictionless ice. It then moves onto a wooden floor, and stops 2.34 s later, 4.81 m past the wood-ice boundary. What is the coefficient of kinetic friction between the puck and the wood?



Finish the Lab

• A 35 kg block of wood is resting on a wooden ramp that is 10° away from horizontal. Rank the following in order from greatest magnitude to smallest magnitude:

A. Drag forceB. Friction forceC. Normal forceD. Weight



Quiz: Chapters 4-5

• Thursday

• Review bookwork and worksheets– Answers to 5.3 homework are on the web site

Projectile Motion Retake

• Thursday or Friday (your choice)• During lunch or after school (your choice)– If you do not finish during lunch, you will not get

extra time.– 100 minute time limit after school

• Tell Mr. Szwast by end of Tuesday when you will take the retake.

Finish the Lab

• The weight of a 70.0 kg tightrope walker standing on the middle of a tightrope (equidistant from the two ends) causes the rope to sag by 5.0°. What is the tension in the rope?



Documents

Warm-Up: October 30, 2015 A 15.0 kg box is sitting at rest on a ramp. The ramp is offset 15.0° from horizontal. a)Draw a free body or force diagram for