Science Chap. 5
Terms
undefined, object
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- What is motion?
- Motion is when an object changes position over time when compared with a reference point.
- What is speed?
- The rate at which an objects moves.
- What is velocity?
- The speed of an object in a particular direction.
- What is acceleration?
- The rate at which velocity changes.
- What is force?
- Force is simply a push or pull.
- What is a newton?
- Newton is a unit in which force is measured by.
- What is net force?
- Net force is the force that results from combining all the forces exerted on an object.
- What is friction?
- Friction is a force that opposes motion between two surfaces that are touching.
- What is gravity?
- Gravity is a force of attraction between objects that is due to their masses.
- What is mass?
- Mass is the amount of matter in an object, and its value does not change.
- To determine if an object is in motion, compare its position over time to a __________ point.
- reference
- Can a moving object be used as a reference point?
- Yes, because if you were on a hot air baloon which is a moving object, you could watch a flying bird overheard, and see it was changing position to your moving balloon.
- _______ is the rate at which an object moves.
- speed
- How fast an object moves depends on the distance traveled and the _______ taken to travel that distance.
- time
- The SI unit for speed is _____.
- m/s (meters/second)
- How do you caculate average speed?
- total distance/total time
- Velocity has speed and ________.
- direction
- To find the resultant velocity, add velocities that are in ________ directions. Subtract velocities that are in __________ directions.
- same;different
- How do you calculate acceleration?
- final velocity-starting velocity/time it takes to change velocity
- Another name for acceleration in which velocity increases is _______ accleration.
- positive
- Negative acceleration in which velocity decreases is called __________.
- deceleration
- How can you recognize acceleration on a graph?
- Velocity increases as time passes.
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True or False?
All forces have size and direction. - True
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True or False?
A force is a push or a pull. - True
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True or False?
Forces are measured in liters. - False
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True or False?
You can exert a push force without there being an object to receive the force. - False
- Forces are unbalanced when the net force is not equal to __________.
- zero
- To start or change the motion of any object, you need an _________ force.
- unbalanced
- Forces are balanced when the net force applied to an object is __________ zero.
- equal to
- What force is responsible for the painful difference between sliding on grass and sliding on pavement?
- The force that is responsible for this is friction.
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True or False?
Friction occurs when the hills and valleys of 2 surfaces stick together. - True
- Pavement creates more friction than grass. Why is that?
- Pavement is rougher than grass.
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True or False?
Friction is affected by the amount of surface that is touching. - False
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What kind of friction is this?
A hockey puck crossing an ice rink. - Sliding friction
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What kind of friction is this?
A crate resting on a loading ramp. - Static Friction
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What kind of friction is this?
Wheeled cart being pushed - Rolling Friction
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What kind of friction is this?
Air rushing past a speeding car - Fluid Friction
- Static friction is at work if you try to drag a heavy suitcase along the floor and the suitcase _________.
- Doesn't move
- As soon as an object starts moving, static friction __________.
- disappears
- How does friction harm the engine of a car?
- It increases temperature and wears down parts.
- Why do you need friction to play sports?
- If there was no friction, you would not be able to pick up a ball or even run.
- What are some ways to reduce friction?
- Use a lubricant, make rubbing surfaces smoother, change sliding friction to rolling friction.
- The force of attraction between two objects due to their masses is the force of _________---.
- gravity
- Does all matter experience gravity?
- Yes, because matter has mass and gravity is the result of mass.
- The force that pulls you toward your pencil is called the __________ force.
- gravitational
- Since all objects are attracted to each other due to gravity, why can't you see the objects moving toward each other?
- The mass of most objects is too small to make an attraction.
- How are objects around us affected by the mass of the Earth?
- The objects on Earth and the mass of Earth have attraction because of Earth's large mass equals up to a large gravitational gorce.
- What did Newton figure out about the moon and a falling apple.
- There was an unbalanced force on the apple to make it fall, just liek the moon, except it needs the force to keep it moving in a circle.
- Newton's law of universal gravitation describes the rlationships between....
- distance, mass, and gravitational force
- Which objects are subject to the law of universal gravitation?
- Satellites, water, frogs, and stars.
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True or False?
If the distance between the objects are the same, the gravitational force between two feathers is greater than the gravitational force between two bowling balls. - False
- If two objects are moved _________ each other the gravitational force between them increases.
- toward
- Why doesn't the sun's gravitational force pull you off the Earth?
- The sun is very far away.
- What would happen to the Earth and other planets in the solar system without the sun's gravitational gorce?
- The planets would not stay in orbit around the sun.
- The strength of the gravitational force exerted by an object depends on the ________ of the object. THe measure of the Earth's gravitational force on an object is the object's _______.
- mass;weight
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Mass or Weight?
Different on the moon - weight
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Mass or Weight?
expressed in newtons - weight
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Mass or Weight?
measured in grams - mass
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Mass or Weight?
measure of gravitational force - weight
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Mass or Weight?
Value doesn't change - mass
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Mass or Weight?
Amount of matter in an object - mass
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True or False?
On Earth, mass and weight are constant which means they are the same thing. - False