Question | Answer |
An airplane flies past a bird. What is the reference point? | The bird...the plane is faster so it MOVES past the bed |
2 factors that determine speed | distance and time |
Difference between speed and velocity | direction |
Example of a balanced force | Picture hanging on a wall |
DIFFERENCE between a force and work | You can apply a force without causing an object to move...WORK requires that the object moves. |
What does an unbalanced force cause? | Change in speed and/or direction |
Friction | opposes motion |
Increases Friction | Sand on ice |
Decreases Friction | Oil |
Law of Universal Gravitation | ALL matter has mass and ALL mass is affected by gravity |
Relationship between mass, distance, and gravity | As mass increases, gravity increases. As distance increases, gravity decreases |
weight | measure of gravitational force |
weight | is NOT constant |
weight | measured in Newtons |
Net Force | Combination of all forces acting on an object |
Acceleration due to gravity | All falling objects accelerate towards the earth at 9.8 m/s/s |
Freefall | The only force acting on an object is gravity |
Freefall | makes an astronaut appear weightless |
momentum | depends on mass and velocity |
Bumper cars collide. The momentum of the faster car... | decreases as the velocity of the slower car increases |
Newton's 1st Law | A moving object that is not acted on will continue moving |
Newton's 1st Law | An object at rest will remain at rest |
Projectile Motion | Combination of horizontal force and vertical force |
A dart's vertical force is a result of... | gravity |
A dart's horizontal force is a result of... | the person throwing it |
When playing darts, aim high because of... | projectile motion |
When you swim and push against the wall of the pool, this is an example of... | Newton's 3rd Law |
Work output | Work done on an object by a machine |
Work input | Work done by you on a machine |
mechanical efficiency | comparison of work output to work input |
Work done on an object depends on ... | force applied and distance the object moved |
How does a ramp make work easier | By increasing the distance and decreasing the force you have to apply |
Formula for work | Force x distance |
What is mechanical advantage? | Force output (force the machine applies) / Force input (force you apply to the machine) |
You apply 10 N of force to a wheel barrow. the wheel barrow applies 50 N of force to a boulder. What is the Mechanical Advantage of the wheel barrow? | MA=WO/WI
MA=50N/10N
MA=5 |
Difference between a fixed and moveable pulley. | Fixed pulley only changes direction of the force...mechanical advantage is always 1 |
Material that allows charges to move easily | Conductor |
Material that does not allow charges to flow easily | Insulator |
Loss of static electricity and charges move off of it | electric discharge |
Part of a cell where charges enter and exit | electrode |
Relationship between resistance and current | As the resistance decreases, the current increases |
3 basic parts of a circuit | power source, wire, load |
Good conductors have low... | resistance |
Circuit that provides only one path to the energy source | Series Circuit |
electric current is made from a ... | changing magnetic field |
This can demagnetize a magnet. | high temperatures |
A coil of wires with an electric current | Solenoid |
Magnets are strongest at the.... | poles |