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29 Cards in this Set
- Front
- Back
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Speed = |
Distance/ Time |
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What does the gradient of a distance-time graph tell you? |
The speed |
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What is the difference between speed and velocity? |
Velocity is speed with direction. Eg Forward motion is positive velocity and backwards is negative |
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How do you find the acceleration on a velocity-time graph? |
The gradient is the acceleration |
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What is an interaction pair? |
A pair of forces which are equal in size, opposite in direction and each acts on a different object |
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If I have an interaction pair where one half has a force of 50N, what is the force on the second half of the pair? |
50N (forces are equal in size) |
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If I push on a wall, what is the direction of force from the wall? |
The wall pushes me backwards |
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Explain what the 'reaction' of a surface is |
The reaction is the response to the force. Eg, I push the floor down so the floor pushes me up in response. |
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Explain what friction is |
Friction is the reaction force which opposes movement |
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Give two scenarios where forces are balanced |
An object resting on a surface: the object pushes down and surface pushes up with the same force. Moving at a steady speed: forces are balanced so your motion is constant |
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If I have more force pushing forward that backward what is my motion? |
Moving forwards |
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If I have more force pushing back that forwards what is my motion? |
Slowing down |
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If I have equal forces pushing forward as moving backward, what is my motion? |
Stationary or moving at a constant speed |
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What is meant by the resultant force? |
The sum of all the forces acting on an object. Eg 20N pushing forward, 10N pusing back therefore total of 10N moving you forwards. |
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If an object has zero resultant force on it, can it be moving? |
Yes-at a constant speed |
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What is momentum? |
mass x velocity |
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What do we mean by change in momentum? |
When the motion speeds up , slows down, stops or starts. |
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Air bags, seat belts and crumple zones are all methods of ensuring safety in a car. Explain how they work. |
All three increase the time for the change in momentum to occur. The longer the time, the smaller the force felt by the person. |
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What is work done and what is the formula? |
Work done is "energy transferred". Work = force x distance |
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I am lifting an object. How could I increase the work done? |
Lift the object higher, increase the weight of the object (force/N) |
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If I do 50J of work, how much energy is transferred? |
50J |
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Lift a box 1m in the air using 80J of energy. How much gravitational potential energy have I given the box? |
80J |
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What is kinetic energy? |
The energy of movement |
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If I increase my kinetic energy, what happens to the amount of work done? |
It increases |
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Change in kinetic energy = work done How does this change if heat is generated? |
Work done is slightly less because some is lost as heat |
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What is gravitational potential energy? |
The energy something has if it is in the air (could fall to the ground) |
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How can I increase an object's GPE? |
Lift the object higher |
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When I drop an object from a height, describe the change in forces |
The objects begins with GPE which is converted to KE as the object falls. |
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If I have 120J of GPE, and there is no air resistance, how much KE can I generate when the object is dropped? |
120J |
