Flashcards in P4.1 Deck (12):

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## 1. What is the equation for average speed?

### -speed (m/s) = distance travelled (m) / tIme taken (s)

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## 2. What is the difference between average speed and instantaneous speed for examples of motion where speed is changing?

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-average speed: how much distance an object covers over a certain time span (doesn’t tell you exact motion at certain points)

-instantaneous speed: an average over a short time interval, tells you the exact speed the object is moving at, at an instant in time

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## 3. What is the displacement of an object at a given moment?

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-its distance from its starting point with an indication of direction

-displacement can be positive or negative depending on its direction

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## 5. What does the gradient of a distance-time and displacement-time graph tell us?

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-Distance-time graph: gradient= speed

-Displacement-time graph=velocity

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## 5. What happens as the gradient gets steeper in a distance/displacement-time graph?

### -the steeper the gradient, the faster the object is going (higher speed)

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## 6. How do you calculate a speed from the gradient of a straight section of a distance-time graph?

### Speed= gradient= vertical/horizontal= distance/time

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## 8. What does acceleration mean in many everyday situations?

### -the change in speed of an object in a given time interval

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## 8. What is deceleration?

### -negative acceleration (if something slows down the change in velocity will be negative)

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## 9. What is the instantaneous velocity of an object?

### -its instantaneous speed with an indication of the direction

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## 10. What happens to velocity if an object moves in the opposite direction?

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-the velocity of an object moving in a straight line is positive if it is moving in one direction and negative if it is moving in the opposite direction

-a line can have the same speed but a different velocity

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## 12. How do you calculate the acceleration from the gradient of a velocity–time graph (or from a speed-time graph in situations where direction of motion is constant)?

### Acceleration= gradient=horizontal/vertical

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