MOTION
What is motion?
Motion is when an object changes its position; is dependent on the reference point.
What is distance?
Distance is how far an object has moved, measured in units like meters, miles, or feet.
What is speed?
Speed is the distance an object travels per unit of time.
On a distance vs. time graph, what does the slope represent?
The slope represents speed.
What is acceleration?
Acceleration is the rate of change of velocity over a period of time.
What is a reference point, and why is it important in describing motion?
An indicator that orients you and is the place from where you measure, record, or witness an event. It is important because motion is always described relative to a reference point.
What is displacement?
Displacement is the distance and direction of an object’s change in position from its starting point to its ending point.
What is the formula for calculating speed?
Speed equals distance divided by time (speed = distance / time).
What does a flat, horizontal line on a distance vs. time graph mean?
It means the object is not moving.
What is the formula for acceleration?
Acceleration = final velocity - initial velocity / by time.
If you’re sitting in a moving car, what could be a good reference point to describe your motion?
The ground, a tree, or a building outside the car could be a good reference point to describe your motion.
If a runner runs around a 1000 m track and ends where they started, what is their distance and displacement?
The distance is 1000 meters, and the displacement is 0 meters.
What is the difference between average speed and instantaneous speed?
Average speed is the total distance divided by total time, while instantaneous speed is the speed at any given moment.
What does a straight, upward-sloping line on a distance vs. time graph indicate?
It indicates the object is moving at a constant speed away from the reference point.
If a car speeds up from 12 km/hr to 23 km/hr in 0.3 hours, what is its acceleration?
The acceleration is 36.67 km/hr2 ((23 - 12) divided by 0.3)
Describe a scenario where an object appears to be at rest from one reference point but moving from another.
Ex: A passenger sitting in a train appears at rest relative to another passenger but is moving relative to someone standing on the platform
A soccer player runs 50 m north and then 20 m south. What is their total distance and displacement?
The total distance is 70 meters, and the displacement is 30 meters north.
What is velocity, and how is it different from speed?
Velocity is speed in a specific direction. Unlike speed, velocity must include direction in the answer.
What does a curved line that gets steeper on a distance vs. time graph show?
It shows the object is speeding up.
A bus accelerates at 13.5 m/s squared from rest to 55 m/s. How long does it take?
It takes ~4.07 seconds (55 - 0 / 13.5).
Why does the choice of reference point affect whether an object is considered to be moving or not?
Because motion is relative; an object may appear to be moving from one reference point but stationary from another, depending on the observer’s position.
A truck drives 4 miles west, then 6 miles north. What is the truck’s distance and displacement?
The distance is 10 miles. The displacement is ~ 7.21 miles northwest.
A car travels 33.75 miles in 0.75 hours. What is its speed?
The speed is 45 miles per hour (33.75 miles divided by 0.75 hours).
How can you tell from a distance vs. time graph if an object is slowing down?
The line will curve and level off, showing the object is covering less distance in each time interval.
A skateboarder starts from 2.2 m/s and accelerates at 4.2 m/s squared for 15 seconds. What is his final velocity?
The final velocity is ~28.63 m/s (4.2 x 15 / 2.2).