6.5.4.1.5 acceleration

Question 1

What is the equation for acceleration

Answer 1

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

Question 2

What is happening when an object is slowing down

Answer 2

It is decelerating

Question 3

What is displacement

Answer 3

Displacement is distance travelled in a stated direction

Question 4

What is the equation for velocity

Answer 4

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

Question 5

What is the unit for acceleration

Answer 5

M/s/s (m/s²).

Question 6

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

Answer 6

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

Question 7

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

Answer 7

the constant velocity is accelerating constantly

Question 8

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

Answer 8

there is no acceleration, the object is constantly moving

Question 9

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

Answer 9

the object is decelerating constantly

Question 10

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

Answer 10

it shows increasing acceleration

Question 11

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

Answer 11

It shows decreasing acceleration

Question 12

What causes an object to accelerate?

Answer 12

a force is applied to that object

Question 13

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

Answer 13

the force in the opposite direction

Question 14

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

Answer 14

Air resistance and friction

Question 15

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

Answer 15

Larger

Question 16

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

Answer 16

Smaller

Question 17

What causes a decrease in velocity within a car/vehicle

Answer 17

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

Question 18

What is centripetal acceleration within a circle?

Answer 18

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.

Question 19

What is the equation for uniform acceleration

Answer 19

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

Question 20

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

Answer 20

9.8m/s ²

Question 21

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

Answer 21

Accelerates, Zero, Terminal

Question 22

What is an objects terminal velocity?

Answer 22

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

Question 23

On a distance time graph what tells us the speed?

Answer 23

The gradient of the line

Question 24

What is the equation for gradient on a distance time graph

Answer 24

Gradient = distance travelled / time taken

Question 25

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

Answer 25

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

Question 26

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

Answer 26

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

Question 27

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?

Answer 27

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