6.5.4.1.5 acceleration Flashcards

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1
Q

What is the equation for acceleration

A

Acceleration (a, m/s²) = change in velocity ( Δv, m/s) / time taken (t, seconds)

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2
Q

What is happening when an object is slowing down

A

It is decelerating

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3
Q

What is displacement

A

Displacement is distance travelled in a stated direction

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4
Q

What is the equation for velocity

A

Velocity ( m/s) = displacement (metres) / time taken (s)

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5
Q

What is the unit for acceleration

A

M/s/s (m/s²).

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6
Q

To calculate the acceleration of a moving object we use the equation?

A

Acceleration (a, m/s/s) =( final velocity (v, m/s) -initial velocity (u, m/s) ) / time taken (t, seconds)

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7
Q

If the line in a velocity time graph has a positive gradient and is directionally proportional what is happening?

A

the constant velocity is accelerating constantly

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8
Q

If the line in a velocity time graph is straight horizontally what is happening?

A

there is no acceleration, the object is constantly moving

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9
Q

If the line on a velocity time graph has a negative gradient, what is happening?

A

the object is decelerating constantly

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10
Q

If the line on a velocity time graph is positively curved what is happening?

A

it shows increasing acceleration

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11
Q

If the line on a velocity time graph is negatively curved what is happening?

A

It shows decreasing acceleration

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12
Q

What causes an object to accelerate?

A

a force is applied to that object

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13
Q

The forward force of an object has to be equal to what, to ensure acceleration?

A

the force in the opposite direction

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14
Q

What are the forces in the opposite direction called? (When driving)

A

Air resistance and friction

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15
Q

To make a vehicle accelerate the forward force has to be _______ than the opposing force

A

Larger

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16
Q

To make the vehicle decelerate the forward force has to be _______ than the opposing force

A

Smaller

17
Q

What causes a decrease in velocity within a car/vehicle

A

Braking, travelling uphill, increasing the mass of the car.

18
Q

What is centripetal acceleration within a circle?

A

when the velocity is constantly changing,( its not slowing down speeding up.) this means the direction towards the centre of the circle is changing- the acceleration is therefore directed towards the centre.

19
Q

What is the equation for uniform acceleration

A

(Final velocity) ² (v, m/s) - (intial velocity) ² (u, m/s) = 2 x acceleration (a, m/s ²) x distance (s, metres)

20
Q

Near the earth’s surface any object falling freely under gravity has an acceleration of about??

A

9.8m/s ²

21
Q

An object falling through a fluid initially ____________ due to the force of gravity. Eventually, the resultant force will be ____ and the object will move at its __________ velocity

A

Accelerates, Zero, Terminal

22
Q

What is an objects terminal velocity?

A

terminal velocity is the maximum velocity (speed) attainable by an object as it falls through a fluid (air is the most common example)

23
Q

On a distance time graph what tells us the speed?

A

The gradient of the line

24
Q

What is the equation for gradient on a distance time graph

A

Gradient = distance travelled / time taken

25
Q

If there a runner travels 120 m in 60 seconds what is the runners speed

A

Speed = distance travelled / time taken
120m / 60s = 2m/s

26
Q

If there is ac curved slope on a distance time graph, what is this telling us?

A

This tells us that the object is constantly increasing in speed (accelerating)

27
Q

If we wanted to know the speed of the object (on a distance time graph) at 100 seconds and 100 metres, how do we calculate its speed?

A

We draw a tangent then find the gradient of that tangent-
For example there’s a distance of 80 seconds for time and a distance of 140 metres for distance.
We then divide 140 by 80 and we get an answer of 1.75 m/s