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GameBoard Force and Motion

Forces Newton Free Body Diagrams

Friction

100

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300

400

500

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300 300 300

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500 500 500

GameBoard Force

100

Describe the two types of forces and give an example.

See Answer

GameBoard Force

100 AContact Force

-push

-pull

Field Force

-gravity

-electrical

-magneticContact Forces

Frictional Force = FfrictTensional Force = FtensNormal Force = Fnorm

Air Resistance Force = FairApplied Force = FappSpring Force= Fspring

GameBoard Force

200

The fundamental units of Force

Answer

GameBoard Force

200 A

N = kg x m/s2

GameBoard Force

300

Analyze the following scenario and give the forces involved: A car being pulled by a towing cable.

Answer

GameBoard Force

300A

-Gravity

-Normal

-Friction

-Applied (pull)

GameBoard Force

400Solve for the components of the net force on a 5 kg balloon moving upward at 2.0 m/s2 at 25o.

Answer

GameBoard Forces

400A

Answer

Fx = ma(cosθ) = 9.1N

Fy = ma(sinθ) = 4.2 N

GameBoard Force

500

Find the net force of the following diagram.

Answer

GameBoard Force

500A

20.6 N at 14.00 South of East

GameBoard Newton

100

Explain the cause of acceleration. Provide the law that explains this

principle.

Answer

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Newton

100AForce

Newton’s Second Law F=ma.

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Newton

200

The term Newton uses in his first law to explain an objects tendency to maintain

its state of motion.

Answer

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Newton

200A

Inertia

An object at rest stays in rest, an object in motion stays in motion, unless acted on

by an unbalanced force.

GameBoard Newton

300

A hammer drives a nail into a piece of wood. Identify the action-reaction pair in this

situation. Which of Newton’s laws explains this situation?

Answer

GameBoard Newton

300 A

The hammer exerts a force on the nail: the wood exerts a force on the wood.

Newton’s 3rd Law

GameBoard Newton

400As a basketball player starts to jump for a rebound, the player begins to move upward faster and faster until his shoes leave the floor. Describe the force of the floor on the shoes in relation to Fg at the moment the

player begins to jump.

Answer

GameBoard Newton

400A

Is greater than the player’s weight

GameBoard Newton

500A 1856 kg truck is moving to the right at a constant speed of 2.17 m/s2 . What is the net force on the car? What would it be if it

were to move in the opposite direction.

Answer

GameBoard Newton

500 A

Zero, at constant velocity the acceleration is zero. Therefore, the net force is zero regardless of

the direction.

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Free Body Diagrams100

Describe three things that are represented in a free-body diagram.

Answer

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Free Body Diagrams 100A

-the object

-forces as vectors (magnitude and direction)

-forces exerted on the object

GameBoard Free Body Diagrams

200

Answer

Create a diagram of a book is at rest on a table top.

GameBoard Free Body Diagrams

200A

In this diagram, there are normal and gravitational

forces on the book.

GameBoard Free Body Diagrams

300

A flying squirrel is gliding (no wing flaps) from a tree to the ground at constant velocity. Consider air resistance. A free body diagram for this situation looks like…

Answer

GameBoard Free Body Diagrams

300A

Gravity pulls down on the squirrel while air resistance keeps the squirrel in the air for a while.

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Free Body Diagrams 400

Answer

Create a diagram for a car that runs out of gas and is coasting

down a hill.

GameBoard Free Body Diagrams

400AEven though the car is coasting down the hill, there is still the dragging friction of

the road (left pointing arrow) as well as gravity and

normal forces.

GameBoard Free Body Diagrams

500

Answer

A box is pulled across a surface at an angle, the box

only moves in the x direction. Write the

equations for the sum of the forces in the x and y

directions in terms of the variables in the picture.

GameBoard Free Body Diagrams

500A

Fx =Ftcosθ-Ff = ma

Fy = Fn+Ftsinθ-Fg = 0 (no movement)

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Friction 100

Compare Kinetic and Static friction.

Answer

GameBoard Friction

100AKinetic friction is the frictional force of an object in motion. Static friction is the frictional force that keeps an object from moving, the minimum amount of force that must be applied for an object to have motion.

GameBoard Friction

200

What is the unit of the coefficient of friction?

Answer

GameBoard Friction

200A

μ does not have a unit because it is a ratio of the Force of friction

and the normal force. Therefore, the units cancel out.

GameBoard Friction

300

Answer

What happens to air resistance when an object accelerates? Why is it considered a form of friction?

GameBoard Friction

300 AIn most cases, air resistance

increases with increasing speed. Therefore, friction is a

retarding force so it can be classified as friction because it is opposing or slowing down

the motion.

GameBoard Friction

400

Answer

There are six books in a stack, each book weighs

5N. The coefficient of static friction between the books is 0.2. Determine what the horizontal force must be to begin sliding the top five books off the

bottom one.

GameBoard Friction

400A

Fx = Fapp-Fs = 0Fapp=Fs=μFn

Fn = FgFg = 5 x 5N = 25N

Fapp = (0.2) 25N = 5 N

GameBoard Friction

500

Answer

An ice skater moving at 10.0 m/s coasts to a halt in 1.0 x 102 m on a smooth ice surface. What is the coefficient of friction between the ice and the skates?

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Friction 500A(1) Fx = Ff = ma

(2) Fy = 0, Fn = Fg

(3) Ff = μFn = μFg Fg = mg

Ff = μmg = ma Eq (1) and (3) combined

μmg = ma m cancels out

μg = a….so… μ = a/g

Solve for a….a = -(vi)2/2∆x = - 0.50 m/s2

μ = a/g = 0.50/9.81 = 0.051

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