Science : What Is Force, Friction, Gravity And Motion

Front 1

In science, a force is a ______ or ______

Back 1

In science a force is a push or pull

Front 2

When one object pushes or pulls another object, the first object is _________ a force on a second object

Back 2

When one object pushes or pulls another object, the first object is exerting a force on a second

Front 3

Which two ways are forces described:

Direction

Velocity

Strength

Acceleration

Back 3

Direction and strength

Front 4

The SI unit used to measure the strength of a force is the

Back 4

Newton

Front 5

The overall force on an object after all the forces are added together is called the

Back 5

Net force

Front 6

When two forces act in the same direction they are ________ together

Back 6

When two forces act in the same direction they are added together

Front 7

Adding a force acting in one direction to a force acting in the opposite direction is the same as adding a__________ number and a ____________ number

Back 7

Positive number

Negative number

Front 8

Unbalanced forces can cause an object to change its motion in three ways. What are they?

Back 8

Unbalanced forces can cause an object to change its motion by

1) starting to move

2) stop moving

3) change directions

Front 9

The following sentence true or false

Unbalanced forces acting on an object will change the object's motion

Back 9

This is true

Front 10

Equal forces acting on one object in opposite directions are called

Back 10

Equal forces acting on one object in opposite directions are called balanced forces

Front 11

Is the following sentence true or false

Balanced forces acting on an object will change the object's motion

Back 11

This is false

Front 12

When you add equal forces exerted in opposite directions, the net force is ________

Back 12

When you add equal forces exerted in opposite directions, the net force is zero

Front 13

Is the following sentence true or false

When two surfaces rub, the irregularities of one surface get caught on those of the other surface

Back 13

False

Front 14

What is friction

Back 14

Friction is the force that two surfaces exert on each other when they rub against each other

Front 15

Friction acts in a direction __________ to the object's direction of motion

Back 15

Friction acts in a direction opposite to the object's direction of motion

Front 16

The strength of the force of friction depends on what two factors

Back 16

How hard the surfaces push together and the type of surfaces involved

Front 17

How is friction involved in sledding and skiing

Back 17

There is little friction between sledding and skiing because snow is smooth

Front 18

Why does some friction occur with seemingly smooth surfaces

Back 18

Even smooth surfaces have irregular surfaces. When a regularity of two surfaces come into contact friction occurs

Front 19

What are the four types of friction

Back 19

Fluid

Sliding

Rolling

Static

Front 20

Which type of friction is this:

An object moves through a liquid or a gas

Back 20

Fluid friction moves an object through liquid or gas

Front 21

And this type of friction, solid surfaces slide over each other

Back 21

Solid Surfaces slide over each other and sliding friction

Front 22

Rolling friction occurs when

Back 22

Rolling friction occurs when an object rolls over a surface

Front 23

Static friction occurs when

Back 23

Static friction occurs when objects are not moving

Front 24

Which kind of friction requires more Force to overcome, rolling friction or sliding friction?

Back 24

Sliding friction

Front 25

What kind of friction occurs when moving parts have ball bearings?

Back 25

Rolling friction

Front 26

The force that pulls objects toward each other is called

Back 26

A force that pulls objects toward each other is called gravity

Front 27

Is the following sentence true or false

The force that makes an apple fall to the ground is the same force that keeps Earth orbiting the Sun

Back 27

This is true

Front 28

What is the universal law of gravitation state?

Back 28

The force of gravity acts between all objects in the universe

Front 29

The force of attraction between two objects varies with what two factors

Back 29

The force of attraction between two objects varies with mass and distance

Front 30

How does oil between machine parts reduce friction?

Back 30

A changes sliding friction to more fluid friction

Front 31

What is weight

Back 31

Weight is the force of gravity on a person or object at the surface of a planet

Front 32

What is the difference between weight and mass

Back 32

Mass is the measure of the amount of matter in an object. Weight is the force of gravity on a person or object

Front 33

Weight is usually measured in_______

Back 33

Weight is usually measured in Newtons

Front 34

Following sentence true or false

On the moon, your mass would be less than it is on Earth but your weight would be the same

Back 34

This is false

Front 35

When is an object said to be in freefall

Back 35

When the only force acting on an object is gravity the object is said to be in freefall

Front 36

Near the surface of the Earth, what is the acceleration of an object due to the force of gravity

Back 36

9.81 m/s2

Front 37

Objects falling through air experience a type of fluid friction called

Back 37

Objects falling through air experience a type of fluid friction called air resistance

Front 38

The greatest velocity a falling object reaches is called

Back 38

The greatest velocity a falling object reaches is called terminal velocity

Front 39

True or false

The greater the surface area of an object, the greater the air resistance

Back 39

This is true

Front 40

An object that is thrown is called

Back 40

An object that is thrown is called projectile

Front 41

Is the following sentence true or false

An object that is dropped will hit the ground before an object that is thrown horizontally from the same height

Back 41

This is true