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Forces&Motion
DDMS 7th grade - Review for Forces & Motion Test
Question | Answer |
---|---|
The state in which one object’s distance from another object is changing | Motion |
A place or point used for comparison to determine if an object is in motion | Reference Point |
The distance that an object travels per unit of time | Speed |
What is the formula (equation) used to find speed | S = D/T; Speed = Distance/Time |
Tell a metric unit for speed | Km/hr; m/s |
Speed in a given direction | Velocity |
On a graph that shows Distance V/S Time, what does the slope of the line represent? | The Speed |
On a graph that shows Distance V/S Time, what does a steep slope mean? | The speed is fast |
On a graph that shows Distance V/S Time, what does a gradual slope mean? | The speed is slow |
On a graph that shows Distance V/S Time, what does a horizontal line mean? | Slope = 0, so the object is not moving. |
The rate at which the velocity of an object changes | Acceleration |
What are the three things that can cause acceleration? | Increase in speed, Decrease in speed, or Change in direction |
What is the metric unit for acceleration? | (m/s)/s or m/s^2 |
What does it mean if an object has a positive acceleration? | It is speeding up |
What does it mean if an object has a negative acceleration? | It is slowing down |
What does it mean if an object has no acceleration (A = 0)? | It is moving at a constant speed |
An object in motion will stay in motion, and an object at rest will stay at rest, unless acted on by an unbalanced force | Newton's First Law of Motion |
F = MA | Newton's Second Law of Motion |
Every Action has an equal and opposite reaction | Newton's Third Law of Motion |
How do balanced forces affect the motion of an object? | Balanced forces cause an object to move at a constant velocity |
How do unbalanced forces affect the motion of an object? | Unbalanced forces cause an object to move with positive or negative acceleration |
A push or pull on an object | Force |
The force of attraction between 2 masses | Gravity |
The force that opposes motion between 2 surfaces that are touching. | Friction |
How is the force of gravity (weight) affected when the mass of an object changes | more mass = more weight; less mass = less weight |
An equal but opposite force exerted by an object when a force acts on it | Reaction |
A boat is traveling 20km/hr toward the east. What property of the boat is being described? | Velocity (Speed & direction) |
If at train takes 6 hours to travel 240 miles, what is the average speed of the train? | Speed = 40 km/hr |
How do balanced forces affect the motion of an object? | Balanced forces cause the object to move with a constant velocity |
You apply 60N of force to move a refrigerator. If the force of friction is 45N, what is the net force acting on the refrigerator? | 60N - 45N = 15N |
How does friction affect a moving object? | Friction slows down a moving object by decreasing the net force |