Motion and Speed
Speed
What is how fast an object moves, or the distance traveled per unit of time
What two factors affect gravitational potential energy?
Mass and height
Newton’s First Law is also called what?
The Law of Inertia
What happens when forces are balanced?
The object’s motion does not change.
Define “criteria.”
Goals or requirements the design should meet.
Formula for speed
Speed= Distance/Time
Which has the greatest GPE: low mass/low height, low mass/high height, high mass/low height, or high mass/high height?
High mass, high height
State the First Law.
An object stays at rest or keeps moving at constant speed unless acted on by an unbalanced force.
What happens when forces are unbalanced?
The object accelerates (changes speed or direction).
Define “constraints.”
Limits or restrictions (materials, time, cost, etc.).
A bird flies 60 m in 12 s. Name the speed.
What is
5 m/s
Formula for GPE
GPE = mass × gravity × height
Formula in Newton’s Second Law?
Force = mass × acceleration
A ball rolls at 0.5 m/s constantly. What’s its acceleration?
Zero
Problem: “Cars speeding cause accidents.” Give one possible criterion.
Example: Must reduce car speeds safely.
On a distance - time graph, what does a flat line mean?
Formula for kinetic energy?
KE = ½ × mass × speed²
A 5 kg object accelerates at 3 m/s². What’s the force?
15 N
Joey pushes left with 500 N; Chanel pushes right with 100 N. Find net force + direction.
400 N left
Give one constraint for that problem
Limited budget, space, or time.
A steeper line on a distance–time graph shows what about speed?
The object is moving faster.
Doubling which increases KE more — mass or speed?
Speed, because it’s squared in the equation.
Complete: “For every action, there is an equal and opposite ____.”
Reaction
Why does a puck slide farther on ice than on pavement?
Less friction on ice.
Give two possible design solutions.
Examples: Speed bumps or automatic speed cameras/police sensors.