61 terms

A passenger in the rear seat of a car moving at a steady speed us at rest relative to?

The front seat of the car

A person walks 1 mile every day for exercise, leaving her front porch at 9:00 am. and returning to her front porch at 9:25 am. What is the total displacement of her daily walk?

0

A person drives north 6 blocks, then turns west, and drives 6 blocks. The driver then turns south and drives 6 blocks. How could the driver have made the distance shorter while maintaining the same displacement?

By driving west 6 blocks from the starting point

A ball is rolled uphill a distance of 5 meters before it slows, stops and begins to roll back. The ball rolls downhill 9 meters before coming to rest against a tree. What is the magnitude of the ball's displacement?

4 meters

Displacement vectors of 4 km south, 2 km north, 5 km south, and 5 km north combine to a total displacement of?

2 km south

Speed is the ratio of the distance an object moves to

the amount of the time needed to travel the distance

Instantaneous speed is measured

at a particular instant

The slope of a line on a distance-time graph is

speed

A horizontal line on a distance-time graph means the object is

at rest

vector addition is used when motion involves

more than one direction, velocity, and one speed

The rate at which velocity changes is called

acceleration

What identifies a change in motion that produces acceleration?

a ball moving at a constant speed around a circular track

Objects in free fall near the surface of the Earth experience

constant acceleration

What's an example the describes constant acceleration due ONLY to a change in direction?

traveling around a circular track

The slope of a speed-time graph indicates

acceleration

An object that is accelerating may be

Slowing down, changing direction, and gaining speed.

What is instantaneous acceleration?

How fast a velocity is changing at a specific instant

The motion of an object looks different to observes in different...?

Frame of references

The SI unit for measuring length is the?

meter

The direction and length of a straight line from the starting point to the ending point of an object's motion is?

Displacement

Displacement and velocity are examples of what? because they have both magnitude and direction.

vectors

The sum of two or more vectors is called the?

resultant vectors

speed is measured in units of?

m/s

A car's speedometer measures

instantaneous speed

v = d/t is the equation for?

speed

The difference between speed and velocity indicates the _____ of motion and speed does not

direction

two or more velocities add by

vector addition

a moving object does not ______ if its velocity remains constant.

accelerate

Freely falling objects accelerate at 9.8 m/s2 because the force of _________ acts on them.

gravity

The velocity of an object moving in a straight line changes at a constant rate when the object is experiencing constant _____

acceleration

The acceleration of a moving object is calculated by dividing the change in _____ by the time over which the change occurs.

speed

Accelerated motion is represented by a _____ line o a distance-time graph.

curved

A car that increases its speed for 20 km/h to 100 km/h undergoes _____ acceleration.

positive

______ ______ is how fast a velocity is changing at a specific instant.

Instantaneous acceleration

Mass:

Is the amount of matter in an object, a measure of the inertia of an object, which depends on the amount of matter the object contains

Weight:

is the force of gravity acting o an object.

Inertia:

An object that is in motion stays in motion and an object at rest stays at rest as long as the net forces acting on that object are zero

Newton's 1st Law states:

The law of Inertia

SI unit for force

Newtons (N)

Weight formula:

w=m.g

1 N:

kg x m/s(2)

N/kg

m/s(2)

Force

Push or pull on an object

Vector

Magnitude and direction

List 4 things that are vectors

Velocity, Acceleration, Force, and Gravity

Force (SI unit):

Newton

Acceleration (SI unit):

m/s(2)

Velocity (SI unit):

1 m/s(2)

Formula for Newton:

km x 1 m/s(2)

What is a net force?

forces combined when they are acting on an object (they can be pushed or pulled)

What do we call it when net forces are zero acting on an object (so there is no change in the object's motion)?

balanced force

True/False: All moving objects are subject to friction.

True

Formula for Newton's 2nd Law of Motion

acceleration= net force / mass or a=f/m

Formula for Momentum

mass x velocity

SI Unit for Momentum

kg x m/s

Newton's Third Law of Motion

For every action there is an equal and opposite reaction.

Whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first object.

Whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first object.

(True or False) Force always exist in pairs.

True

(True or False) Only when equal and opposite forces act on the same object do they result in a net force of zero.

True

(True or False) Momentum is a vector

True

Law of Conservation

If no net force acts on a system, then the total momentum does not change.

What is conserved when 2 objects collide in a closed system?

Momentum