Force
Motion
Newton's Laws of Motion
Calculating
Misc.
100
What is a force?
A force is a push or a pull.
100
What is motion?
Motion is when an object changes position over time relative to a reference point.
100
What is inertia? Give an example.
Inertia is the tendency of all objects to resist any change in motion. A car has inertia when it slows down to a complete stop.
100
A boy rode his bike 900 meters in 60 seconds. What was his speed?
15 m/s.
100
What is an increase in acceleration called? What is a decrease in acceleration called?
Positive acceleration and negative acceleration (deceleration).
200
Is pushing a grocery cart an example of a balanced or unbalanced force?
This is an example of an unbalanced force because it produces a change in motion.
200
What are three common units we use when measuring motion?
1. Meters per second 2. Kilometers per hour 3. Feet per second 4. Miles per hour
200
What does mass have to do with inertia? Please give one example.
An object that has a small mass has less inertia than an object with a large mass. -Changing a planes direction vs. a bikes direction.
200
A plane traveled 600 miles West landing in Wyoming. It then traveled another 400 miles reaching its final destination. It completed this in 8 hours. What was the planes speed?
125 mi/hr West.
200
Why can't you feel the attraction of you being pulled towards other objects due to gravity?
You can't feel this because the mass of most objects is too small to cause a force large enough to move objects toward each other.
300
What is friction, what causes is, and what does the amount of friction depend on?
- Friction is a force that opposes motion between two surfaces that are in contact. -Microscopic hills on an object that come in contact with other microscopic hills and valleys on another object causes friction. - The amount of friction depends on the force applied on this object.
300
What is acceleration? What are the two types?
The rate at which velocity changes speed or direction - not only how much velocity changes, but how fast. Positive acceleration & negative acceleration (deceleration).
300
Is this statement true or false. If false correct the statement. All forces act by itself - a force never acts in a pair.
False. All forces act in pairs - a force never acts by itself.
300
A car is traveling South. It accelerates from 50 miles per hour to 80 miles per hour in 15 seconds. What was the cars acceleration?
2 mi/sec South.
400
How can you reduce and increase friction? Please give two examples.
Reduce friction: apply lubricants, switch sliding kinetic friction to rolling kinetic friction. Increase friction: Makes surfaces rougher, increase the force pushing the surfaces together.
400
What is the formula for acceleration and what unit do you use?
A = VF - VS/ T Units- m/s squared
400
What is part one of the second law? Please give an example.
The acceleration of an object decreases as the mass increases. -Pushing a full grocery cart vs. an empty cart.
400
What is the velocity of a car that travels 75 km in 1.5 hours East?
50 km/hr East.
400
What is the difference between weight and mass? When do these forces change?
Weight- A measure of the gravitational force on an object. -Changes when gravitational force changes Mass- Amount of matter in an object. -Does not change
500
What are the two parts to the Law of Universal Gravitation? Please provide and example for each.
Part 1: Gravitational force increases as mass increases. - there is a larger force between a larger object (an elephant) and the earth rather than a smaller object (a cat) making it harder to pick up the elephant (because of the large force) and easier to pick up the cat. Part 2: Gravitational force decreases as distance increases. -There is a larger amount of gravitational force on earth because we are closer to the sun. Uranus does not have as much gravity because it is further from the sun.
500
When does velocity change?
velocity changes when speed or direction changes.
500
What would the result be if force pairs acted on the same object.
The net force would always be 0N and nothing would ever move.
500
A basketball rolls down a ramp for 20 seconds. Its starting velocity was 10 m/sec and its final velocity was 12 m/sec. What was the balls acceleration?
.1 m/s South.
500
True or false. If false, correct it. The velocity of an object is always in the same direction as the force applied.
False. The acceleration is always in the same direction as the force applied.
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