Balanced and Unbalanced, Contact and Non-Contact Forces

Balanced and Unbalanced,

Contact and Non-Contact Forces

compiled by Ma. Katerina Janubas

Multiple Choice

What is a force?

• Motion

• Work

• Push or a pull

• What Luke Skywalker does

Multiple Choice

When is there a change in motion?

• When the forces are balanced.

• When the forces are unbalanced.

• Never.

• When the forces are equal.

Multiple Choice

A force in the opposite direction to the motion of the object will cause the object to

• speed up

• slow down

• turn

• crash

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Multiple Choice

Can balanced forces exist in moving bodies/objects?

• No. Balanced forces keep objects stationary.

• Yes, balanced forces exist in moving bodies with constant velocity. 

Multiple Choice

Balanced forces can keep objects stationary or in constant velocity (speed and direction).

• True

• False

Multiple Choice

Forces come in pairs. 

• True

• False

Multiple Choice

If the forces acting on an object are balanced and the object is in motion, then it will continue in motion with the same velocity.

• True

• False

Multiple Choice

Slide a book across a table and watch it slide to a rest position. The book in motion on the table top does not come to a rest position because of the absence of a force; rather it is the presence of a force - that force being the force of friction - that brings the book to a rest position.

• True

• False

Multiple Choice

In the absence of a force of friction, the book would continue in motion with the same speed and direction - forever (or at least to the end of the table top)!

• True

• False

Multiple Choice

You and your dad are moving the couch from one side to another. Your dad pushes with a force of 35 N to the right and you push with a force of 25 N right. What is the net force on the couch?

• 60 N right

• 10 N left

• 60 n right

• 50 N left

Multiple Choice

If two forces are said to be equal in magnitude and have opposite direction, then the object is said to have ___________.

• Balanced forces

• Unbalanced force

• Accelerating

• None of these

Multiple Select

What effect do forces have on an object?

• They can change the motion of an object

• They can make objects bigger

• They can make objects change from one form into another

• They can make objects smaller.

Multiple Choice

A wheeled cart is moving to the right at a constant speed.  Two forces of equal magnitude are acting upon the cart. Which of the following best describes the forces and motion of the cart?

• Balanced Forces, Constant Speed

• Balanced Forces, Acceleration

• Unbalanced Forces, Constant Speed

• Unbalanced Forces, Acceleration

Multiple Choice

Which could be an example of an unbalanced force?

• A plate sitting on a dining table

• A ball at the top of a hill that is not moving

• Earth orbiting the Sun 

• A baseball that has been thrown to home plate.

Multiple Choice

Which could be an example of a balanced force?

• An asteroid moving at a constant speed through space 

• A car accelerating from a stop sign

• A box of dishes falling from a counter 

• A rocket taking off 

Multiple Choice

Which of the following objects will experience an unbalanced force?

• A bike rider on a smooth and level road, pedaling at a constant rate.

• A train pulling on another train, each with the same amount of force.

• A chair sitting on the floor with balanced forces acting in opposite directions.

• A ball rolling across the floor with friction acting in the opposite direction.

Multiple Choice

If these teams are pulling with the same amount of force what will happen?

• The boy in blue will win.

• They will not move at all.

• The boy in red will win.

• Both will fall down.

Multiple Choice

What is the net force?

• 40 N left

• 0 N Balanced Forces

• 400 N right

• 40 N right

Multiple Choice

How will this object move? 

• a combined force of 80 N, but it won't move. 

• 20 N, to the right. 

• 20 N, to the left. 

• a combined force of 80 N, to the right

Multiple Choice

In a tug of war the left team pulls with a force of 200N. The right team pulls with a force of 150N. What is the resultant force?

• 50N to the left.

• 350N to the left.

• 350N to the right.

• 50N to the right.

Multiple Choice

What is the net force?

• 400 N Up

• 400 N Down

• - 400 N Down

• 800 N Down

Multiple Choice

Which of the blocks above has balanced forces acting on it?

• A

• B

• C

• D

Multiple Choice

These are two forces acting on an object and causes a change in motion. These forces are not equal in size.

• Force

• Balanced Force

• Unbalanced Force

• Net Force

​Please take a mandatory 3-minute screen break now.

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​Forces can also be classified as contact or noncontact forces. Either way, these forces can cause motion.

Multiple Choice

A contact force is from

• objects physically touching

• far apart objects

• not touching object

• always a pull

Multiple Choice

A non-contact force is between

• two objects that aren't touching

• two objects that are touching

• the ground and wheels

• you and me

Multiple Choice

The three examples pictured are of

• Non-contact Forces

• Contact Forces

Multiple Choice

The force between the phone and the mount is a

• contact force

• non-contact force

Multiple Choice

Gravity is a

• Contact Force

• Myth

• Non-contact Force

Multiple Choice

Friction is a

• Contact Force

• Myth

• Non-contact Force

Multiple Choice

Which is an example of a non-contact force?

• elastic force

• normal force

• applied force

• electric force

Multiple Select

Air Resistance Force

• Contact Force

• Non-Contact Force

Multiple Choice

As a bike rider goes up a hill, the force of gravity acts to ____.

• Increase the weight of the rider

• Increase the acceleration of the rider

• Decrease the mass of the rider

• Decrease the speed of the rider

Multiple Choice

Why must the space shuttle use great force to get into outer space?

• Earth's spin pushes the shuttle

• Weather system moves near the shuttle's launch area

• Earth's gravity pulls on the shuttle

• The shuttle is exposed to high temperatures.

Multiple Choice

Which of the following keeps the planets in our solar system in orbit around the Sun?

• Atmospheric pressure

• Electromagnetic energy

• Magnetism

• Gravitational force

Multiple Select

What type of contact force is transmitted through a rope, string or wire when pulled by forces acting from opposite sides

• Friction

• Gravity

• Normal

• Tension

Multiple Select

The greater the roughness the greater the friction.

• True

• False

Multiple Choice

The force that resists sliding between two touching objects is called _____________________

• normal force

• contact force

• non-contact force

• friction

Multiple Choice

What forces are acting on the bag, and what are their relative magnitudes and directions?

• The force of gravity on the bag and the force of the hook. The force of gravity is larger than the force of the hook. The force of gravity points downward and the force of the hook points upward.

• The force of gravity and the tension force of the string. The force of gravity is exactly balanced by the force of the string attached to the bag. The force of gravity points downward and the force from the string points upward.

​Let us reflect.

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Open Ended

What are the "unbalanced" forces in our lives that drive us to continue living, loving, and moving forward?

This is the end of your first Physics asynchronous lesson.

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