Physics Chapter 2 Test

Kinematic Equations

A formula that relates the variables of motion: displacement (d), initial velocity (vi), final velocity (vf), acceleration (a), and time (t). These equations help predict the future position and velocity of moving objects under.

Position

A specific location of an object in space relative to a reference point.

Velocity

The speed of an object in a particular direction. it is a vector quantity, meaning it has both magnitude (how fast the object is moving) and direction (the direction in which the object is moving). For example, if a car is moving north at 60 mph, its velocity is 60 mph north.

Average Acceleration

The change in velocity during some measurable time interval divided by that time interval.

vf-vi over tf-ti

Instantaneous Acceleration

The change in velocity at an instant of time.

Displacement

A vector quantity that refers to the change in position of an object. It is defined as the straight-line distance from the initial position to the final position, along with the direction. Unlike distance, which is a scalar quantity and only considers the magnitude, displacement takes both magnitude and direction into account.

Free Fall

The motion of an object falling under the influence of gravity alone, with no other forces acting on it, such as air resistance. In free fall, the only acceleration acting on the object is due to gravity, which is approximately 9.80 m/s² on Earth. This means the object's speed increases by 9.80 m/s every second it falls.

Acceleration due to Gravity

The rate at which an object accelerates when it is in free fall, solely under the influence of Earth's gravitational pull. This acceleration is constant and is approximately 9.80 m/s² on the surface of the Earth. This means that for every second an object is in free fall, its velocity increases by 9.80 m/s.

Air Resistance

The force that opposes the motion of an object through the air. It acts in the opposite direction to the object's velocity and increases with the object's speed. Air resistance depends on several factors, including the object's speed, surface area, shape, and the density of the air.

What are the different ways of describing motion?

Words, graphs, motion diagrams, and mathematical models.

How are position, velocity, time, and acceleration related?

They are all related through kinematic equations. Velocity is the rate of change of position, and acceleration is the rate of change of velocity. Time is the variable that allows us to track these changes.

How does an object’s speed change as it falls?

Its speed increases due to the force of gravity. This acceleration due to gravity is approximately 9.80 m/s² on Earth. So, as time progresses, the object's velocity increases by 9.80 meters per second for each second it falls.

In what case would an object be speeding up?

a. +a, -v

b. +a, V=0

c. a=0, +v

d. -a, -V

-a, -V

Which of the following free falling bodies has the greatest acceleration?

a. Bullet fired into the air.

b. A ruler dropped off a building.

c. An egg thrown downward at the ground.

d. Once in free fall, they all have the same acceleration.

Once in free fall, they all have the same acceleration.

Consider drops of water from a leaky faucet.

As they fall, they…

get farther apart

_________ accelerated motion means that velocity changes by equal amounts in equal time intervals.

Uniform

An object that ___________ is speeding up, slowing down, or turning.

accelerates

______ can be described in different ways: with words, graphs, motion diagrams, and mathematical models.

Motion

A sprinter runs a race on a straight track starting from rest and reaches a top speed of 10 m/s. The speed of the sprinter is _________, the velocity of the sprinter is ________, and the sprinter is _____________.

changing, changing, accelerating

A train moving at 20 km/h comes to a stop at a station along a straight section of track. The speed of the train is ________, the velocity of the train is ________, and the train is __________.

changing, changing, accelerating

A race car travels along a straight section of a race track at a constant rate of 90 m/s. The speed of the car is ________, the velocity of the car is _________, the car is ______________.

constant, constant, not accelerating

A cyclist travels around a curve at a constant rate of 13 m/s. The speed of the cyclist is ________, the velocity of the cyclist is ________, and the cyclist is ___________.

constant, changing, accelerating

When a projectile is launched upward the velocity and acceleration are in the same direction.

false

As an object falls, its acceleration increases.

false

At the top of the projectiles path acceleration =0 m/s/s.

false

As an object falls freely, the distance it covers each second is the same. 

false

An object is thrown upward and returns to its original position. It returns to the original position with the same speed, but a different velocity.

true

At the top of the projectile’s path, velocity=0.

true