Motion Basics
What is the branch of physics that describes how things move?
Kinematics
What does a positive acceleration mean?
The object is speeding up.
What does a horizontal line on a position vs. time graph represent?
The object is not moving.
What does “vᵢ” represent in a kinematic equation?
Initial velocity.
Why does a skydiver eventually stop accelerating during free fall?
Air resistance balances gravity (terminal velocity).
What is the difference between distance and displacement?
Distance is total path traveled; displacement is change in position (straight-line from start to finish).
What does a negative acceleration (deceleration) mean?
The object is slowing down.
What does the slope of a position vs. time graph represent?
Velocity
What is the formula for final velocity when acceleration and time are known?
v𝒇 = vᵢ + a·t.
When you press the gas pedal, what happens to acceleration and velocity?
Acceleration increases, and velocity increases over time.
If a car moves 60 meters east in 3 seconds, what is its average speed?
20 m/s.
A runner’s velocity changes from 4 m/s to 10 m/s in 3 seconds. What’s their acceleration?
2 m/s².
What does the slope of a velocity vs. time graph represent?
Acceleration
A car starts from rest and accelerates at 3 m/s² for 4 seconds. What’s its final velocity?
12 m/s.
A car and a truck have the same velocity, but the truck has more mass. Which has greater momentum?
The truck
If an object has zero acceleration, what can you say about its velocity?
It’s constant (not changing).
An object moves at 15 m/s north and another moves 15 m/s south. How do their velocities compare?
They have the same speed but opposite directions.
If a velocity-time graph shows a straight line sloping downward, what does that mean?
The object is slowing down (negative acceleration).
If you know an object’s acceleration, time, and initial velocity, how can you find its displacement?
Use x = vᵢt + ½a·t².
Why do objects in free fall not depend on their mass to accelerate?
Because gravity accelerates all objects equally (9.8 m/s²).
What are the three key variables studied in kinematics?
Displacement, velocity, and acceleration.
What does it mean if acceleration = 0 m/s² but velocity ≠ 0 m/s?
The object is moving at constant speed.
What does the area under a velocity vs. time graph represent?
Displacement
At the highest point in a ball’s upward motion, what is true about its velocity and acceleration?
Velocity = 0; acceleration = -9.8 m/s² downward.
A train moves at constant velocity. What can you say about the forces acting on it?
They are balanced (net force = 0).