⭐️Topic SP2 - Motion And Forces Flashcards Preview

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Flashcards in ⭐️Topic SP2 - Motion And Forces Deck (36)
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1

What is acceleration?

How much velocity changes in a certain time

2

How do you work out the resultant force of two forces on an object?

You add them if in the same direction or subtract them if opposite direction

3

What does Newton’s first law state?

A moving object will continue to move at the same speed and direction unless acted upon by an external force
Or
An object in motion stays in motion unless acted upon by an external force

4

What is centripetal force?

The resultant force that causes an object to change direction - so it moves in a circular path

5

Give examples of centripetal force?

Friction, tension (e.g. wires of a fairground ride) and gravity

6

What is mass? When does it change?

The amount of matter there is in an object. It only changes when the object itself changes

7

What is weight?

A measure of the pull of gravity there is on an object

8

What device can be used to measure weight?

A force meter as they have a spring which stretches as the force on it increases

9

What is gravitational field strength in earth?

9.8 N/kg but in calculations can be rounded to 10N/kg

10

How can you calculate weight?

Weight (N) = mass (kg) x gravitational field strength (N/kg)

11

What is Newton’s 2nd law?

Force N = mass kg x acceleration m/s squared

12

What is the inertial mass of an object?

The force on the object / the acceleration produced by the force

13

What’s Newton’s third law?

Action reaction forces

14

Give characteristics of a pair of action reaction forces

They both are the same size
both act in opposite directions
They are the same type of force

15

What’s the difference between action reaction forces and balanced forces?

Action reaction forces act on different objects but balanced forces all act on the same object

16

What is momentum?

A measure in the tendency of an object to keep moving or how hard it is to stop it moving

17

Is momentum a vector or scalar?

Vector

18

How do you calculate momentum?

Momentum (kg m/s)= mass (kg) x velocity (m/s)

19

How can momentum and acceleration be combined in a formula?

F = m(v-u) / t

20

What is the rule for conservation of momentum?

When moving objects collide, total momentum of both objects is the same before the collision as it is after the collision as long as no external forces are acting upon it

21

What’s thinking distance?

The distance traveled by a driver while reacting to a situation

22

What’s breaking distance?

The distance travelled by the vehicle while the breaks are working to stop it

23

What’s stopping distance equal to?

Thinking distance + breaking distance

24

What is a reaction time?

The time between the person detecting their stimulus and their response

25

What can be used to measure response times?

Using computers or electric circuits

26

What’s the typical reaction time to a visual stimulus?

0.25 seconds

27

What increases reaction time?

By being under influence of drugs, alcohol or dit reactions like using your phone

28

What may increase the breaking distance?

By having worn out breaks as less friction is created, if the road is wet or there’s loose gravel as friction is reduced, if the tyres are worn out as friction is reduced, if the vehicle has a larger mass as more force is needed to decelerate it

29

Why is overall stopping distance for cars less than lorries

As cars will automatically have a smaller breaking distance as they have a lower mass

30

What is the formula for work done?

Work down (J) = force (N) x distance moved in the direction of the force (m)