Extra Chapter 4 Problems (.pdf)

Thursday, November 4

1st
Projectiles Lab due
Intro. to Chapter 4
Newton's 1st and 2nd laws of motion
Comparing force and mass; S.I. & B.E.S. and their units
*The four fundamental forces
Defining weight as a special case of force
• 5th/6th
• Projectiles Lab due
• Intro. to Chapter 4
• Newton's 1st and 2nd laws of motion
• Comparing force and mass; S.I. & B.E.S. and their units
• *The four fundamental forces
• Defining weight as a special case of force
• 7th
• Projectiles Lab due
• The four fundamental forces
• Defining weight as a special case of force

Friday, November 5

• 1st
• The four fundamental forces
• Calculating weight on Earth and Moon, etc.
• 5th
• The four fundamental forces
• Calculating weight on Earth and Moon, etc.
• 7th
• Newton's second law
• Calculating weight on Earth and Moon.

1st/2nd
Balanced and unbalanced forces, resistive forces, net force and equilibrium
Example: A 3200 kg truck undergoes acceleration from an 6000 N force from the engine. What is its acceleration rate? How much time to accelerate to 29 m/s (about 65 mph)? What about if it has 1000 kg of cargo aboard? What if 250 N of friction exists?
A 43 kg boy pushes horizontally on the ground with a force of 82 N. A frictional force of 3 N exists. What is the boy's acceleration rate?
*Equilibrium with the bird on a wire problem
More examples of balanced and unbalanced force problems
5th/6th
Balanced and unbalanced forces, resistive forces, net force and equilibrium
Example: A 3200 kg truck undergoes acceleration from an 6000 N force from the engine. What is its acceleration rate? How much time to accelerate to 29 m/s (about 65 mph)? What about if it has 1000 kg of cargo aboard? What if 250 N of friction exists?
• A 43 kg boy pushes horizontally on the ground with a force of 82 N. A frictional force of 3 N exists. What is the boy's acceleration rate?
• *Equilibrium with the bird on a wire problem
• More examples of balanced and unbalanced force problems
• 7th
• Calculating weight on Earth and Moon, etc.
• Balanced and unbalanced forces, resistive forces, net force and equilibrium
• Example: A 3200 kg truck undergoes acceleration from an 6000 N force from the engine. What is its acceleration rate? How much time to accelerate to 29 m/s (about 65 mph)? What about if it has 1000 kg of cargo aboard? What if 250 N of friction exists?
• A 43 kg boy pushes horizontally on the ground with a force of 82 N. A frictional force of 3 N exists. What is the boy's acceleration rate?

Tuesday, November 9

1st/2nd
P. 109; 1-2, 5-7, 11 due
Go over problems
*Two people pull on ropes connected to a 520 N crate. They each pull with a force of 130 N but are pulling 30° from the centerline of motion. What is the acceleration rate of the crate? What if a friction force of 220 N exists? What if the friction force is 80 N?
5th/6th
P. 109; 1-2, 5-7, 11 due
Go over problems
*Two people pull on ropes connected to a 520 N crate. They each pull with a force of 130 N but are pulling 30° from the centerline of motion. What is the acceleration rate of the crate? What if a friction force of 220 N exists? What if the friction force is 80 N?
7th
P. 109; 1-2, 5-7, 11 due
Go over problems
Equilibrium with the bird on a wire problem
Two people pull on ropes connected to a 520 N crate. They each pull with a force of 130 N but are pulling 30° from the centerline of motion. What is the acceleration rate of the crate? What if a friction force of 220 N exists? What if the friction force is 80 N?

Thursday, November 10 and Friday, November 11 – No School – Parent/Teacher conferences

Monday, November 14

• P. 109; 15 to 20 due
• Collect problems
• Work on Force Lab

Tuesday, November 15

• Intro. to friction and the friction lab
• Friction formula and its values
• *Finish force lab data collection and analysis
• Collection friction lab data

Wednesday, November 16

• Return and review problems from last week
• *Inclined plane
• Atwood machine

Thursday, November 17

• 1st
• Some more examples: A 55 kg box is pulled along with a force of 70 N by a rope that makes a 40° angle with the horizontal. How fast is the box moving after 2.0 s if it starts at rest? What if the coefficient of friction is 0.2? (How much more force is required to make it move at constant speed?
• A 40 kg lawnmower is pushed along the ground at a constant speed. The person pushes on the handle with an angle of 45° and a force of 200 N. Calculate the coefficient of friction.
• Work on problems
• 5th
• Some more examples: A 55 kg box is pulled along with a force of 70 N by a rope that makes a 40° angle with the horizontal. How fast is the box moving after 2.0 s if it starts at rest? What if the coefficient of friction is 0.2? (How much more force is required to make it move at constant speed?
• A 40 kg lawnmower is pushed along the ground at a constant speed. The person pushes on the handle with an angle of 45° and a force of 200 N. Calculate the coefficient of friction.
• Work on problems
• 6th/7th
• Some more examples: A 55 kg box is pulled along with a force of 70 N by a rope that makes a 40° angle with the horizontal. How fast is the box moving after 2.0 s if it starts at rest? What if the coefficient of friction is 0.2? (How much more force is required to make it move at constant speed?
• A 40 kg lawnmower is pushed along the ground at a constant speed. The person pushes on the handle with an angle of 45° and a force of 200 N. Calculate the coefficient of friction.
• Work on problems

Friday, November 18

P. 111; 24–26, 29–31 due
Friction on an inclined plane
A 15 kg crate resting on a 35° ramp has a static coefficient of friction of 0.40 and a kinetic coefficient of friction of 0.35. Calculate:
• Minimum force to keep it from moving
• Force needed to move it up the ramp at constant speed
• Force needed to move it down the ramp at constant speed
• What if we want to move it 2.2 m up the ramp in 4.5 s?

Monday, November 21

Force Lab due
Collection Friction Lab data
*Atwood's machine
Forces on an inclined plane

Tuesday, November 22

• P. 112, 35-38 due

Wednesday, November 23

Extra lab time
Work on homework and lab

Thursday, November 24 through Monday, November 28 – No School – Thanksgiving Break

Wednesday, November 30

P. 112, 39-42 due
Friction on an inclined plane problem where mu=tan theta and limiting angle of repose
Ratio of a/g is mu for flat surfaces...

Thursday, December 1

Work on problems

Friday, December 2

Chapter 4 Problems due

Monday, December 5

Work on review
More example problems

Tuesday, December 6

Chapter 4 Review
Go over solutions
What does mu depend on?

Wednesday, December 7

Chapter 4 Test

Thursday, December 8

Friction Lab due