Intro to Physics
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Who was Sir Isaac Newton?
A 1700's scientist. He developed the laws of motion.
What is speed?
Distance traveled divided by the time it took to travel the distance.
E.g. 50 meters traveled per second (50 m/s)
What is friction?
The force two surfaces exert on each other when they touch/rub against each other.
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What is drag?
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the resistive force exerted on an object moving through a fluid (air or water), acting opposite to the direction of motion
What question does physics ask?
How (how things happen).
What is the difference between balanced and unbalanced forces acting on an object?
Balanced forces do not result in a change in motion due to the equal forces acting on the object.
Unbalanced forces result in a change in motion in the direction of the greater force.
What is the difference between speed and velocity?
Speed is distance divided by time, Velocity is speed with a direction.
What is the difference between weight and mass?
Weight is a measure of the gravitational force on an object, mass is how much "stuff" is in one place.
What was the size of the parachutes that had the lowest terminal velocity?
Large radius/diameter.
What do we do in physics? What two concepts/subjects do we use to study the world?
Applied mathematics
State one of Isaac Newton's three laws of motion.
1. An object at rest stays at rest. An object in motion stays in motion unless an unbalanced force acts on it.
2. The force acting on an object is equal to the mass of that object times its acceleration.
3. Every action (or force) has an equal and opposite reaction (or force).
When is an object in motion?
When its distance from another object is changing.
Define static friction.
Static friction is the friction that acts on objects that are not moving.
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Why did parachutes with a smaller radius fall faster? Your answer must include "terminal velocity" as a part of your answer.
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They had less surface area, increasing their terminal velocity.
What is the ultimate goal of physics?
To understand the universe around us.
What are the steps for solving a problem with Newton's second law?
1. Draw an FBD
2. Add forces (vectors) in X and Y Directions.
3. Solve
What is the difference between a scalar and a vector?
Direction and magnitude
Define air resistance and terminal velocity.
Air resistance: a type of fluid friction that occurs when objects fall toward earth.
Terminal velocity: the fastest an object can fall, this is the speed an object is traveling when the gravitational force acting on it (downward) equals the air resistance pushing back on it (upward).
How is air resistance related to terminal velocity?
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What elements do you need to include on a graph?
TAILS! +key and line of best fit :)
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What is Inertia?
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How much an object resists changing its direction.
What does acceleration mean?
Acceleration is the process of increasing or decreasing speed over time, which looks like this: m/s2 (m/s/s).
Using the following equations, answer the question below.
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Final Velocity = Initial Velocity + Gravity x Time
How fast would a piece of wood be falling on Mars (Gravity = 3.9 m/s/s) if a woodchuck could chuck wood at a Velocity of 10 m/s, and the wood was chucked 8 seconds ago?
41.2 m/s
(use the Final Velocity equation, we are looing for how fast the wood is falling, which is a velocity)
What is Hooke's Law? Did it have any affect on the construction of the parachutes? Why?
Hooke's law states that the force required to extend or compress a spring by a distance is directly proportional to that distance. No, it did not have a significant affect on the construction of the parachutes because the materials used to suspend the parachutes did not have low enough k-value to play an effect.