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17 Cards in this Set
- Front
- Back
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What is the formula for weight |
Weight = mass x gravitational field strength |
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What are the two important effects of gravity? |
One the surface of a planet, it makes all things accelerate towards the ground. It gives everything to the ground. |
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What is the difference between mass and weight? |
Mass is the amount of stuff in an object. Weight is a force caused by the pull of gravity. |
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Why will your mass be the same on the earth and the moon? |
Your mass always stays the same. |
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Why would your weight change on a different planet? |
The gravitational field strength differs on other planets. |
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Explain why a cars velocity is not constant |
Velocity is the speed of an object in a given direction, and a car changes direction often. This means that the velocity of a car is not constant. |
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What is the formula for force? |
Force = Mass x Acceleration |
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What is friction caused by? |
When two surfaces are in contact, or when an object passes through a fluid. |
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What is the relationship between speed and drag? |
The higher the speed, the higher the drag. |
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What is Terminal Velocity? |
When the acceleration and frictional force of an object is equal. |
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Why, on the moon, do all objects fall at the same speed. |
There is no air, meaning air resistance cannot cause things to fall at different speeds. |
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What do LDRs do? |
A resistor that is dependent on the intensity of light. The brighter the light, the lower the Resistance. The dimmer the light, the higher the resistance. |
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What does a thermistor do? |
A temperature dependant resistor.
The higher the temperature, the lower the resistance. The lower the temperature, the higher the resistance. |
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Describe, both in terms of energy transfer and forces how cars brake. |
When the driver applies his foot to a brake, the brake presses against the wheel. This causes friction, converting kinetic energy into heat energy. The temperature of the bake increases and the car slows down. |
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What is the formula for Work Done? |
Work = Force x Distance moved |
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Describe the forces on a moving car |
Driving Force is caused by a car's engine. Air resistance and the friction of the wheels works against this driving force. As the driving force increases, so does the air resistance until both forces are balanced. It has reached a terminal velocity and moves at a constant speed. |
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Describe the forces acting on a skydiver |
Weight caused by gravity makes the skydiver accelerate towards the ground. As the skydiver's velocity increases, so does his air resistance until they balance. This causes a terminal velocity; the skydiver accelerates at a constant speed. The skydiver opens the parachute and the surface area for air resistance increases, so the air resistance is higher than the velocity. When the air resistance and the velocity balance, the skydiver reaches a lower terminal velocity and slows down until he reaches land. |
