Speed
A runner covers 100 m in 20 s. What is their speed?
5 m/s
Maria walks 200 m to the park, then 200 m home. What is her displacement?
0, no displacement
A distance–time graph shows a straight line sloping upward. Is the object moving at a constant speed, accelerating, or stopped?
Constant speed
Which has direction: speed or velocity?
Velocity = Speed + Direction
The tendency of an object to resist a change in speed or direction.
Inertia
A car drives 300 km in 5 hours. What is its speed?
60 km/h
A student walks 10 m forward and then 10 m back. Why is their distance different from their displacement?
Distance is the total length of a path traveled.
Displacement is a straight line distance and direction from start to end
On a position–time graph, a flat (horizontal) line means what?
The object is at rest.
Which unit is correct for speed: m/s, kg, or liters?
m/s
An object at rest stays at rest and an object in motion stays in motion with the same speed and direction unless the object is acted upon by an unbalanced force.
A cyclist rides 1,200 m in 200 s. What is their speed in m/s?
6 m/s
Jacob walks 80 m east, then 30 m west. What is his displacement?
50 m east
Two students’ position–time graphs are shown. Student A’s line is steeper than Student B’s. Who is moving faster?
Student A
What is the formula for speed?
Speed = Distance/Time
True or False - an object with more mass has more inertia
True
A cheetah runs 500 m in 20 seconds. What is its speed?
25 m/s
A runner goes 400 m around a track and ends at the start. What is their displacement?
0 displacement, start and end points are the same.
A speed–time graph shows a line sloping downward. What does that mean about the object’s motion?
The object is returning to its starting point
Can an object have a speed of 0 but still have a displacement that is not 0? Explain.
yes, an object can have speed = 0 while still having a nonzero displacement.
True or False - it is more difficult to change the motion of an object with more inertia
True
A plane flies 720 km in 8 hours. What is its speed in km/h?
90 km/h
A student walks 10 m north, then 30m south. What is their distance? What is their displacement?
Distance = 40m
Displacement = 20m south
A car drives 3 km east, then 4 km west. What is the total distance? What is the displacement?
Distance = 7 km Displacement = 1 km west
On a position–time graph, an object moves away from the start for 5 seconds, stops for 5 seconds, then returns back to the start in the next 5 seconds. Sketch what this graph would look like.
NA
Using Newton's first law of motion and the term inertia, explain why a dog would have trouble changing its motion on ice.
The dog is in motion towards the toy and when it tries to stop, there isn't an external force to help (like friction). Therefore the dog has inertia forward and it is difficult to change motion in another direction.