Formulas
Define speed and give the formula for average speed using distance and time.
Speed is the rate of motion; average speed = distance/time (Distance ÷ Time).
In physical science, what is a push or a pull called?
Force
What is friction? Name two types of friction and give one example of each.
Friction is the force resisting motion between surfaces. Types: sliding (hands rubbing) and rolling (bike tires).
On a distance-versus-time graph, what two variables are plotted?
Displacement and time.
If a bicyclist travels 30 kilometers in two hours, what is her average speed? Show your calculation.
30 km÷2 h=15 km/h.
State Newton’s first law in your own words and give a classroom example
Newton’s first law: objects remain at rest or in uniform motion unless acted on by a net external force (example: a book stays on a table until pushed).
What type of friction is air resistance classified as? Explain how air resistance affects a falling object.
Air resistance is a type of friction that opposes motion through air and increases with speed and surface area.
What does a horizontal (flat) segment on a speed vs. time graph represent?
A flat line shows constant speed (zero acceleration).
What is the difference between speed and velocity? Give an example that illustrates the difference
Speed is scalar (magnitude only); velocity is vector (magnitude + direction). Example: 10 km/h north.
State Newton’s third law and give an example involving a bat and a ball.
Newton’s third law: for every action there is an equal and opposite reaction (bat hit ball: action on ball, reaction on bat).
Define terminal velocity
Maximum speed and abject can fall at
Given a speed vs. time graph where speed increases linearly from 00 to 6 m/s over 3 s, calculate the acceleration. Show work.
Acceleration = (6 m/s−0 /3)
s=2
A roller coaster is moving at 10 m/s10 m/s at the top of a hill and 22 m/s22 m/s at the bottom two seconds later. Calculate the average acceleration and show your steps
Change in speed = 22−10=12 m/s22−10=12 m/s; time = 2 s2 s so average acceleration = 12 m/s2 s=6 m/s22 s12 m/s=6 m/s2.
According to Newton’s second law, write the relationship between net force, mass, and acceleration and explain each term. (Include the equation.)
Newton’s second law: Fnet=m⋅aFnet=m⋅a where FnetFnet is net force, mm is mass, aa is acceleration.
Compare the forces of gravity and air resistance on a skydiver before and after she opens her parachute.
Gravity stays essentially the same (weight), but air resistance increases greatly after parachute opens, reducing net downward acceleration.
ow far did a ball move in the final 2 seconds if its speed was constant at 3 m/s3 m/s during those two seconds? Show the calculation.
Distance = speed × time = 3 m/s×2 s
=6
Describe instantaneous speed and explain one method (experimental or from a graph) for estimating it.
Instantaneous speed is the speed at a single moment (e.g., read from a tangent line on a distance-time graph or using a speedometer).
A rocket lifts off the ground. Which Newton’s law best explains the lift-off and why? Provide a short explanation using the law’s statement.
Newton’s third law explains lift-off: rocket exhaust pushes down (action), rocket is pushed up (reaction).
Explain rolling friction vs. sliding friction and why the amount of friction changes with surface area and texture.
Rolling friction occurs when an object rolls (tires), sliding when surfaces slide past each other; friction depends on surface characteristics and normal force, not directly on surface area in simple models.
Explain how you would determine whether a graph shows deceleration. What features or slopes would you look for?
Deceleration appears as a negative slope on a speed vs. time graph (speed decreasing with time). A downward-sloping line indicates deceleration.