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Science P2 Topic 3
Edexcel GCSE additional science physics: motion and forces
Question | Answer |
---|---|
What are scalar quantities and some examples? | Quantities that only have a size e.g. speed (the time an object takes to move a certain distance, m/s) and distance (how far something moves, including the distance it moves backwards, m) |
How would you work out speed on a distance-time graph? | Speed is the gradient (slope) of the line- the steeper the line, the faster the speed |
What are vector quantities and some examples? | Quantities with a speed and direction e.g. forces, momentum, displacement, velocity (speed in a stated direction), acceleration |
What do velocity time graphs show? | Velocity, time, acceleration and displacement |
How would you work out displacement on a velocity-time graph? | The area under the graph |
How would you work out acceleration on a velocity-time graph? | The gradient of the line |
What is acceleration? | The change in velocity in a certain amount of time, measured in m/s/s (causes an object to speed up, slow down or change direction) |
What is a force? | A push or a pull that makes objects change speed, shape or direction |
What is a free-body diagram? | A diagram that shows all the forces acting on a body at one time- showing size and direction of each force |
What happens if the forces on an object are balanced? | The object will continue moving at the same velocity or will stay stationary |
What is a resultant force? | The overall force acting on an object- calculated by adding forces in the same direction and subtracting those in opposite directions- an object will accelerate in the direction of the resultant force |
What is the size of acceleration dependent on? | Force and mass of the object |
What are action and reaction forces? | Forces of equal size and opposite direction that act on two different bodies that interact |
What is gravitational field strength? | The strength of gravity, measured in N/kg |
What is the gravitational field strength of the earth? | 10N/kg |
What do all bodies do in a vacuum? | they all accelerate at the same rate |
What is terminal velocity? | Fastest speed when air resistance and thrust / weight are balanced |
Explain the velocity-time graph for a parachutist | 1)parachutist jumps out of plane falls quickly as air resistnace isn't acting 2) the parachutist reaches terminal velocity 3) parachute opens and air resistance increases 4) air resistance is resultant force 5) parachutist reaches terminal velocity |