Force is used in many different ways everyday. This mom is__________
the groceries in her cart.
A force is any push or pull. A force is needed to make a change in an object's movement. A force can make an object speed up, slow down, or change direction.
Forces have a magnitude and a direction. The magnitude of a force is how strong the force is. Magnitude is measured in units called newtons (N).
Question 2
2.
Select the images that show force (remember a force is a push or pull).
Question 3
3.
Other Answer Choices:
Question 4
4.
Question 5
5.
A force has a magnitude and a______________ . The magnitude is how
___________ the force is. Magnitude is measured in a unit called
____________ .
Other Answer Choices:
map
Newtons
grams
strong
direction
weak
Checking for Understanding:
1. Forces can make an object slow down, speed up, or change directions.
2, Forces have a magnitude and a direction.
A force is any push or pull. This push or pull can be classified into two different types: contact and non-contact forces. Contact forces occur when two objects are touching. Select the pictures to learn more about contact forces.
Non-contact forces can affect motion without an object being directly touched by another object. Select the pictures to learn more about non-contact forces.
Question 6
6.
__________forces happen when an object is touched by another object.
__________forces can affect motion without an object being directly touched by another object.
Golf is a sport that has contact forces. When the golfer hits the golf ball with her club, the club is making contact with the ball. This affects the golf ball's motion and sends it flying towards the hole.
Question 7
7.
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Question 8
8.
Other Answer Choices:
Check for Understanding:
1. Contact forces occur when an object is touched by another object.
2. Non-contact forces can affect motion without an object being directly touched by another object.
Gravity is a non-contact force. All objects exert gravity on all other objects, but only huge objects, like planets, have enough gravity to be felt. When an object has more mass, it has a stronger gravitational pull.
Question 9
9.
Which objects exert gravity (read the text above)?
Question 10
10.
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Question 11
11.
Which planet has the strongest gravitational pull?
Question 12
12.
Check for Understanding:
1. All objects exert gravity on all other objects.
2. Objects with a large mass, like planets, have enough gravity to be felt.
Another non-contact force is magnetism. Magnetism is a force that pushes and pulls on other objects. Magnetism repels or attracts certain metals. Magnets are attracted to the metals like iron, cobalt, and nickel.
Magnets will also exert forces on other magnets. Every magnet has two opposite poles, or ends: a south pole and a north pole. Magnets with opposite poles attract one another, while magnets with similar poles repel one another.
Question 13
13.
Touch the end of a bar magnet that would be attracted to the south pole of another magnet.
Question 14
14.
Touch the end of a bar magnet that would repel the north pole of another magnetic.
Question 15
15.
A magnet__________be attracted to paper clips. A magnet__________
be attracted to a drinking glass.
As a metal object gets closer to a magnetic pole, the magnetic force increases. Magnetic force is the strongest at each magnetic pole. On Earth, the magnetic force is strongest at the North Pole and the South Pole. A compass uses this magnetic force to move it's needle.
The horseshoe magnet below is exerting a stronger force on the ring magnet than the bar magnet. This is because the north pole of the horseshoe magnet is very close to the ring magnet, while the south pole of the horseshoe magnet is farther away from the bar magnet. Magnetic force is stronger when the poles of two magnets are closer together.
Question 16
16.
Question 17
17.
Click the spots on this magnet where the magnetic force is the strongest.
Question 18
18.
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Check for Understanding:
1. Magnets repel or attract certain metals.
2. All magnets have a north and south pole.
3. Magnetic force is greatest at the poles.
Lastly, there is a non-contact force known as electricity. Electric forces act between electrically charged objects. An atom contains electrons that are negatively charged and protons that are positively charged. To become electrically charged, an object gains or loses these electrons. When an object gains electrons, it has a negative charge because it has more electrons. When an object loses electrons, it has a positive charge because it has more protons.
Objects often gain or lose electrons when they are rubbed together. Have you ever rubbed your feet on the ground and then gotten a shock after touching metal? That is because friction caused electrons to move from the carpet into your body. Then, when you touched the metal, the electrons went into the metal all at once, causing a shock.
Oppositely charged objects are attracted to each other and stick together. Objects with the same charge repel one another and move away. For example, a negatively charged comb will attract pieces of paper to it.
Question 19
19.
When an object gains electrons, it has a__________charge. When an object loses electrons, it has a__________charge.
Question 20
20.
Sonya is brushing her hair with a brush. When she puts the brush down near some scraps of paper, the paper moves towards the brush.
While brushing her hair, Sonya's brush became electrically charged. When she put it down near the small scraps of paper, the brush attracted the paper.
Check for Understanding:
1. To become electrically charged, an object gains or loses electrons.
2. Objects often gain or lose electrons when objects are rubbed together.
3. Objects with opposite electric charges attract one another.
4. Objects with the same electric charge repel one another.
Question 21
21.
Question 22
22.
Question 23
23.
1. A force is any push or a pull. All forces have a magnitude and a direction.
2. Forces can make an object speed up, slow down, or change directions.
3. A contact force is a force that occurs when two objects touch.
4. A non-contact force is a force that occurs without two objects touching each other directly.
5. Examples of non-contact forces are gravity, magnetism, and electricity.
Question 24
24.
Other Answer Choices:
Question 25
25.
Question 26
26.
Question 27
27.
Question 28
28.
Question 29
29.
Question 30
30.
Question 31
31.
Drag the correct picture to the right box.
Which of the following describe a force (remember, a force is a push or a pull)?
a cat jumping from a bed to a dresser
a mule pulling a cart up a hill
a person squeezing lemons for lemonade
Sort the pictures into the correct categories.
Sort the pictures into the correct categories.
Sort the objects based on the amount of gravity they exert on other objects.
Which of the following choices describes a gravitational force?
A chicken pecks the ground for food.
A girl drops a penny from a bridge into the water.
A magnet sticks to a refrigerator.
You and a classmate are playing with magnets. You put two circular magnets on a pencil, and one of them starts to float. Your friend sees the floating magnet and says, "It is magic!" What would you say in response?
"They are opposite poles, and they are attracting each other."
"They are the same poles, and they are repelling each other."
"They are the same poles, and they are attracting each other."
"They are opposite poles, and they are repelling each other."
Drag each doughnut magnet to the location where it will cause the greatest attractive force with the horseshoe magnet.
Which answer choice is an example of an electric force?
A child uses a magnet to stick her art project on the fridge.
A cow brushes up against a plant, and seeds stick to the cow.
Tape is used to hold wrapping paper together on a present.
The laundry comes out of the dryer and is stuck together.
What is the definition of force?
any kind of charge
any push or pull
a positive charge
something that can't be seen
What is a contact force?
a force that occurs when two objects do not touch
a force that occurs when two objects touch
a force that causes an object to stay still
a force that causes an object to move downwards
What is the definition of non-contact force?
a force that living things have on objects on planet Earth
a force that causes objects to stop moving
a force that can affect motion without two objects touching one another
a force that humans have on other objects in the universe
Which kind of force is present in each of these pictures?
What can a force do to an object?
make an object change direction
make an object slow down
make an object stop moving
make an object speed up
all of the above
The ball had a downward force of 10 __________.
liters
newtons
watts
meters per second
Malik headed the ball in her soccer game. What kind of force did she use?
contact force
electric force
non-contact force
gravitational force
Which is an example of a non-contact force?
a football player tackling another player
a man closing the dishwasher
a person pulling a paperclip across a table with a magnet
a car crashing into a tree
For an object to become electrically charged, it would have to gain or lose __________.
protons
neutrons
electrons
newtons
Why would two apples sitting next to each other not attract each other?
Gravity between small objects is weak.
Gravity between small objects is strong.
Gravity does not affect small objects on Earth.
Gravity only affects large items like moons and planets.
You are playing with two unlabeled magnets. When you put them near each other, they push away from each other. Which two poles of the magnets might be interacting? (choose 2)
