# Motion and Energy

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• Created by: Eloise
• Created on: 23-04-16 14:28
What is acceleration?
How quick the velocity is changing
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Velocity time graphs : what is meant by flat sections? Uphill/Downhill sections? a curve? How do you work out distance traveled?
Flat: Steady speed. Uphill/Downhill: Accelerating/decelerating. Curve: Changing acceleration. Distance traveled: area under graph
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What is a resultant force?
Overall force on a point or object which decides its motion thus changing it's velocity
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If there is a zero resultant force acting on a stationary object and a moving object, what happens? and a non zero resultant force on a moving object?
The stationary object remains stationary, the moving object continues at the same velocity. The moving object will accelerate
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When two objects interact, the forces they exert on each other are...
equal and opposite (directions)
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What is terminal velocity and explain it using an example
resistance compared to weight. Parachuter: Starts off with the weight being larger than the air resistance so they accelerate towards the ground as the parachute is opened the resistance is larger so they'll be slowed down but the forces then balance
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What is the braking distance and thinking distance and what factors effect them?
B:distance the car travels under breaking force (speed, good brakes, good tires, grip) T:distance the vehicle travels during the drivers reaction time (speed, dopeyness)
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Explain how an elastic object stores work done as elastic potential energy
apply a force to an object causing it to stretch or change shape, the work done to change its shape is stored as elastic potential energy and when the force is removed it is converted into kinetic energy to return to it's original shape
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What are regenerative brakes?
instead of converting kinetic energy into heat energy it reverses the vehicles motor, this acts as generator converting kinetic energy into electrical and storing it as chemical.
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Name 4 safety features of a car and what they do
Crumple zones: kinetic energy converted by change of shape, increase impact time. Seat Belts: stretch, reduce force. Side impact bars: direct kinetic energy away. Air bags: slow you down gradually and surface hitting prevention
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How is static energy formed Give examples of two materials
By friction, when insulating materials are rubbed together electrons will be transfer from one to the other. Polythene becomes negative, Acetate become positive
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What is Current, Potential Difference and Resistance?
C: flow of electric charge around the circuit. PD:driving force that pushes current around. R:anything in the circuit which slows down the current
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Potential difference-current graphs:what does it look like for resistors? Lamps? Diodes?
R: directly proportional L: as temperature increases so does resistance so it's curved D: current only flows through diode in one direction, high resistance in other direction
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What are the three rules of a series circuit?
1) Potential difference is shared 2) Current is the same everywhere 3) Resistance adds up
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What are the two rules of a parallel circuit? What are the advantages?
1) Potential difference is the same across all components 2) Current is shared between branches A: everything can be turned on separately and everything gets full voltage from the battery
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How do you work out the time period and the frequency of a trace from an oscilloscope?
TP; measure horizontal distance and multiply by the timebase. F: 1 divided by time period
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State the names and colours of the three core cables in a wire and say what they do
Live wire is brown and alternates between high negative and positive voltage. Neutral wire is blue and is at zero volts. Earth wire is yellow and green, it's for safety and protection
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What does a fuse and circuit breaker do?
F: melts due to surge in current, cutting off live supply, isolating the appliance. CB: surge in current opens up a switch to break circuit, easily reset, expensive
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## Other cards in this set

### Card 2

#### Front

Velocity time graphs : what is meant by flat sections? Uphill/Downhill sections? a curve? How do you work out distance traveled?

#### Back

Flat: Steady speed. Uphill/Downhill: Accelerating/decelerating. Curve: Changing acceleration. Distance traveled: area under graph

### Card 3

#### Front

What is a resultant force?

### Card 4

#### Front

If there is a zero resultant force acting on a stationary object and a moving object, what happens? and a non zero resultant force on a moving object?

### Card 5

#### Front

When two objects interact, the forces they exert on each other are...