Science Chapter 1 Test (8th grade)

This flashcard set covers most of the notes (not example calculation problems). Some terms are repeated because I personally need more practice with those terms, and think they are important to know. While this is a comprehensive study tool make sure to also use practice problems, the study guide, practice short answer questions, and use any other study resources. If something is incorrect or needs to be added please contact me. Good luck!

Force

A push or pull applied to an object

Net force

when 2 or more forces act on an object at the same time

Balanced forces

When net forces cancel each other out and net force is zero

What is intertia? What does it relate to?

An object’s tendency to resist a change of motion. Directly relates to mass. (takes more force to change bowling ball motion than ping pong ball motion)

Who is Sir Isaac Newton and what years was he alive

British scientist. 1642-1727

What is Sir Isaac Newton known for?

Known for his laws of motion (newton’s laws of motion)

What is newton’s first law of motion?

An object at rest tends to stay at rest unless acted upon by an outside force. An object in motion tends to stay in motion unless acted upon by an outside force.

Newton’s first law is also known as what

The law of Intertia

What invisible force will cause you to stop if you slide across your kitchen floor in socks

Friction

What invisible force will cause you to fall to the earth if you fall of your bed

Gravity

Explain why you are thrown forward in your car if you are in an accident

Because your body was traveling at the same rate of the car when it stopped. You were pulled back by your seatbelt

What does Newton’s second law state?

explains the relationship between force, mass and acceleration.states that the acceleration of an object is in the same direction as the net force on the object.

What is the equation for newton’s second law of motion

Force=mass times acceleration

What units do we use for the following (2nd law)

Force

Mass

Acceleration

Force: Newton’s
Mass: Kilograms

Acceleration: m/s²

Friction

The force that opposes the sliding motion of two surfaces that are touching each other

What 2 things does friction depend on?

Type of surface, amount of force pushing the surfaces together

Static friction

The frictional force that prevents two surfaces from sliding past each other

Sliding friction

The opposite of static friction. Occurs between 2 objects that are sliding past one another.

Rolling friction

Type of friction that exists between an object that is rolling and the surface it is rolling on

What is air resistance

Resistance caused by the air (if there was no air 2 objects would fall at same speed even if different)

What 3 things does air resistance depend on

Speed, size, and shape of object

What is terminal velocity

Fastest speed a falling object will reach (have it b/c of air resistance)

What 2 things are equal when terminal velocity is reached?

Force of gravity and force of air resistance

What is newton’s 3rd law

For every action there is an equal and opposite reaction

Though action and reaction forces act on different objects they are __________

Equal

Even though action and reaction forces are equal they are not ______________ because they act on different objects

Balanced

The idea of newton’s third law is what gets us into what place

space

An object that is moving has momentum which is related to what?

How force would be needed to change its motion

To find momentum what is the equation

Momentum = mass times velocity

In equation of momentum = mass times velocity what do you measure momentum, mass, and velocity in?

Momentum is kg m/s, mass is kg, and velocity is m/s

Can momentum be lost?

No only transferred from one object to another

When objects collide what of each object determines the overall effect of the collision

Momentum

Motion

Occurs when an object changes position relative to a reference point

Distance

How far an object has traveled

Displacement

Distance and direction of an object’s change in position from starting point

Speed

The distance an object travels per unit time; rate of change in position

How to calculate speed

v=d/t

Give definition and example of insrantaneous speed

Speed at any given point in time

Driving a car and looking down at speedometer

Give definition and example of average speed

Total distance traveled divided by total time

Taking a road trip

Give definition and example of constant speed

Speed that does not vary

Putting a car in cruise control

Motion of an object can be plotted on what kind of graph where x axis is time and y axis is distance

Distance-time graph

The slope of a line on a distance-time graph gives the ____ of an object in motion

Speed

Velocity

Includes speed of an object and the direction of its motion

What is the difference between speed and velocity?

Velocity includes direction whereas speed does not

What is the difference between positive and negative acceleration?

Positive means object is speeding up negative means object is slowing down

Acceleration

Rate of change of velocity

Acceleration occurs when an object changes what?

Speed, direction, or both

Formula for acceleration?

acceleration =(Vf-Vi)/t

Friction

The force that opposes the sliding motion of two touching surfaces

Friction is caused by microscopic bumps on surfaces that are called what?

Microwelds

give a description and an example of static friction

Friction in which two surfaces are not moving past each other

Pusing a fridge across a floor

give a description and an example of sliding friction

Friction where two surfaces slide past one another

Sledding down a hill

give a description and an example of rolling friction

Friction between a rolling object and the surface it rolls on

Skateboard moving on the ground

give a description and an example of fluid friction

Friction when an object moves through fluid, meaning either a liquid or gas

Skydiving

Air resistance

Friction-like force that opposes motion of objects that move through the air

What things does air resistance depend on

Size, speed, and shape of object

Newton’s second law of motion

A net force acting on an object causes the object to accelerate in the direction of the force

Acceleration is determined by what?

The size of force and the mass of an object

Formula that goes along with newton’s second law of motion

force = mass times acceleration

Momentum

Property of moving object resulting from its mass and velocity

formula to find momentum

Momentum (p)= mass times velocity

Gravity

Any two masses that exert an attractive force on each other

Gravity depends on what two things between objects

Mass and distance

Weight

Gravitational force exerted on an object measured in Newton’s

Projectile

anything that is thrown or shot through the air

A projectile follows what knd of path

A curved path

A projectile has these two kinds of motion

Horizontal motion and vertical motion

Centripetal acceleration

Acceleration toward the center of a curved or circular path

Centripetal force

Force acting toward the center of a curved or circular path

how do you calculate net force if forces are going in smae direction

Add the forces together

How do you calculate net force if forces are going in opposite directions

Subtract the smaller force from the larger force. the net force points in the direction of the larger force.

On a distance vs. time graph what does a flat horizontal line indicate

Object is at rest

On a distance vs. time graph what does a straight diagonal line slanting up indicate

Moving at a constant speed

On a distance vs. time graph what does a curved line bending upwards indicate

Object is accelerating (speeding up)

On a distance vs. time graph what does a steeper line indicate

A higher speed

On a speed vs. time graph what does a flat horizontal line mean

Object is moving at a constant speed

On a speed vs. time graph what does a diagonal line slanting up mean

Object is accelerating (speeding up)

On a speed vs. time graph what does a diagonal line slanting down mean

Object is decelerating (slowing down)