Bell Ringers

Bell RingerAug 14, 2012

• Grab an article from the box and read it. Don’t get lost in the unusual names or words. Simply highlight/underline them and move on. Then use the back to analyze the story.

*Remember, I expect you silent during the bell ringer.

Bell RingerAug 15, 2012

• Grab a fishboning explanation and guide from the “box”. Use the article from yesterday(fire in the lab) and use the fishboning method to:– Write the main idea– Support your idea– Give take away message

*Remember, I expect you silent during the bell ringer.

Bell RingerAug 16, 2012

Questions for the Author

• Grab the reading strategy from the “box”. Read it and do it using the “Fire in the lab” story from Tuesday.

*Remember, I expect you silent during the bell ringer.

Bell RingerAug 17, 2012

A safe lab culture article

• Grab the article from the “box”. Read it.

*Remember, I expect you silent during the bell ringer.

Bell RingerAug 20/21, 2012

• If it takes one second for light to travel from the moon to the earth and 8 minutes for light to travel from the sun to the earth, how far away are the moon and sun?

Bell RingerAug 22/23, 2012

• Write as many scalar quantities as you can think of.

• Write as many vector quantities as you can think of.

• Find the component form of the following vector.

Bell RingerAug 24/27, 2012

• We are going to the library.• You will need to create:1. Gmail account2. Edmodo account3. Dropbox account

Bell RingerAug 30/31

• What is gravity? • Where does it come from?• What kinds of things have gravity?• I have two masses. One is a basketball. The other is a

5lb bag of potatoes. If I hold them at the same height and drop them at the same time, which one hits the ground first?

• Do they have a constant velocity?• Do they have the same gravitational force acting on

them?

Bell Ringer Sept 4/5• Consider the graph at the right. The object whose motion

is represented by this graph is ... (include all that are true):1. moving in the positive direction.2. moving with a constant velocity.3. moving with a negative velocity.4. slowing down.5. changing directions.6. speeding up.7. moving with a positive acceleration.8. moving with a constant acceleration.

Bell Ringer Sept 6/7• A car (A) moves to the left with speed 40km/h

(with respect to the road). Another car (B) moves to the right with speed 60km/h(also with respect to the road). Find the relative velocity of B with respect to A.

• After 5s a car is moving 20km/h. It uniformly accelerates to 60km/h in 15s. If the car were to continue to accelerate at the same rate how fast would it be going after a total time of 1 min. Use a graph to estimate the value.

• An ice cube melts at a constant rate. For every increases of 3degress in the room temperature ice will melt 6ml of water. Use a graph to determine the how much ice has melted if the room temperature has increased a total of 13degress.

• A car (A) moves to the left with speed 40km/h (with respect to the road). Another car (B) moves to the right with speed 60km/h(also with respect to the road). Find the relative velocity of B with respect to A.

Sept. 17/18

• What is a force?http://www.youtube.com/watch?v=GmlMV7bA0TM&feature=relmfu• Why does the Earth spin? Explain.http://www.youtube.com/watch?v=TQxeutcYP6I&feature=edu&list=PL772556F1EFC4D01C• If you stopped the Earth from spinning, would

it stay stopped or not? Explain.

Sept 19

• What are Newton’s Three Laws?• What is wrong with Derrick’s Laws

Sept. 25/26

• What is momentum? Example.• What is impulse? Example.• What is the Law of Conservation of

Momentum? Example

Sept 27/28

A motorboat traveling 4 m/s, East encounters a current traveling 3.0 m/s, North.

1. What is the resultant velocity of the motorboat?2. If the width of the river is 80 meters wide, then

how much time does it take the boat to travel shore to shore?

3. What distance downstream does the boat reach the opposite shore?

http://www.physicsclassroom.com/class/vectors/u3l1f.cfm#soln(See examples 1 and 2 for explanations)

Oct 1/2

At a railway station, two trains slowly collide in order to “couple” (join together). If one train of mass 12000kg is moving at 0.75m/s and the other of mass 3000kg is stationary, calculate the velocity of the two as they move away.

Answer: 0.6m/s

Oct 3/4• Ball A travelling with speed V in the direction shown

makes a glancing collision with stationary ball B of the same mass. After the collision the balls move off with speeds Va and Vb in the directions show on board. Which one of the following is true? Explain.

• A) Va cosα = Vb cosβ• B) Va sin α = Vb singβ• C) V = Va cosα + Vb cosβ• D) V = Va + Vb

• Answer: A • Since momentum is a vector quantity,

direction is also conserved i.e. momentum in the +x to –x direction = 0. Va cosα = Vb cosβ

Oct.5/8

Come in have a seat.Expected grades. We have a force quiz – 30minStart collision lab – 45min

Oct. 9/10

1. Define weight2. What is Newton’s 3rd Law3. Use the given triangle to solve for “x”4. Add the following vectors:

a) 4m/s @45degb) 9m/s @150dg

Oct. 11/121. A 0.1kg ball moves at 5m/s bounces off a vertical

wall without a change in its speed. If the collision with the wall lasted for .1s what force was exerted on the wall?

2. A ball of mass.25kg moves on a frctionless horizontal floor and hits a vertical wall with speed 5m/s. the ball rebounds with speed 4m/s. If the ball was in contact with the wall for .15s, find the average force that acted on the ball.

3. Bullets of mass .03kg are being fired from a gun with a speed of 300m/s at a rate of 20 bullets per second. What force is being exerted on the gun?

Oct 16/17• A man of mass “m” stands on a cart of mass “M”

that rests on a horizontal frictionless surface. If the man begins to walk with velocity “v” with respect to the cart, how will the cart move?

• What happens when the man gets to the edge of the cart and stops walking?

Oct 22

• A stationary body(A) of mass 12kg is hit by a 4kg mass(B) moving at a velocity of 12m/s. Body A moves off at an angle of 60degree to the left of the original direction. Body B moves off at an angle of 30 degrees to the right of the original direction.

• What are the speed of the two masses after the collision?