Motion Madness
Define "magnitude"
Answer: The "how much" or the numerical value of a number.
What is the specific difference between speed and velocity?
Velocity includes direction (it's a vector), while speed does not (it's a scalar)
Which of Newton's Laws explains why you should wear a seatbelt to prevent your body from continuing forward when a car stops?
Newton’s 1st Law (The Law of Inertia)
Define "Momentum" and list the two factors it depends on.
Momentum is mass in motion; it depends on an object's mass and its velocity.
What is a "projectile"?
An object moving through the air, affected only by gravity (and air resistance, though we often ignore it in basics).
Name three examples of scalar quantities
Time, Distance, Speed, Temperature, or Mass
In our coordinate system, if an object is moving "South" or "to the Left," do we represent its velocity with a positive or negative sign?
A negative sign (Negative Y for South, Negative X for Left).
If an object has "Balanced Forces" acting on it, what is its Net Force, and what does that tell you about its acceleration?
The Net Force is 0 N, and the acceleration is zero (it is either at rest or moving at a constant velocity)
What is the "Impulse-Momentum Theorem" in simple terms?
Impulse is equal to the change in momentum of an object ( J= change in momentum)
In projectile motion, do the horizontal and vertical components of motion affect each other?
No, they are independent.
What two things does a vector quantity have that a scalar does not
Magnitude AND direction
A car travels 551 km in 6 hours. What is its average speed
91.83 km/hr (Speed = Distance / Time).
A swimmer pushes backward on the water to move their body forward through the pool. Which of Newton's Laws does this demonstrate?
Newton’s 3rd Law (Action-Reaction).
What is the difference between an elastic and inelastic collision?
In elastic collisions, objects bounce off each other; in inelastic collisions, they stick together.
If you drop a ball and throw another one horizontally at the same time from the same height, which hits the ground first
They hit the ground at the same time (because gravity acts on both vertically at the same rate).
Name three examples of vector quantities.
Displacement, Velocity, Acceleration, Force, or Momentum
Define acceleration in your own words and list the three ways an object can accelerate.
Acceleration is the rate at which velocity changes. An object accelerates by speeding up, slowing down, or changing direction.
A 10 kg sled is pushed to the right with a force of 50 N, but a friction force of 10 N pulls back to the left. What is the Net Force and the Acceleration?
Net Force = 40 N to the right; Acceleration = 4 m/s² (a=f/m)
If an object is at rest, what is its momentum?
Zero (because its velocity is zero).
At the very peak (highest point) of a projectile's arc, what is its vertical velocity?
Zero (0m/s)
How is a variable represented to show it is a vector
With a Vector Bar over the variable.
A cyclist is traveling at an initial velocity of 0 and accelerates to $8 m/s in 3 seconds. What is their acceleration?
2.67m/s2
Newton's 2nd Law is often written as the formula F=ma. According to this relationship, if you keep the force the same but double the mass of the object, what happens to the acceleration?
The acceleration is cut in half (Inversely proportional).
If two skaters push off each other from rest, and the total momentum before they push is zero, what is the total momentum of the "system" after they push?.
Zero. According to the Law of Conservation of Momentum, the total momentum remains constant unless an outside force acts on it.
Describe the horizontal velocity of a projectile throughout its entire flight (assuming no air resistance).
It remains constant (it does not change because there are no horizontal forces).