Forces and motion (topic 2) Flashcards Preview

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Flashcards in Forces and motion (topic 2) Deck (19)
1
Q

What is Newton’s first law?

A

An object will continue moving in the same direction and speed until an external force acts upon it.

2
Q

What is Newton’s second law?

A

A larger force is required to push a larger mass. The acceleration is dependent on the amount of force applied.

3
Q

What is Newton’s third law?

A

Every action has an equal or opposite reaction.

4
Q

What the formula for weight?

A

Weight(N) = mass(Kg) x acceleration due to gravity(9.81)

5
Q

What is the value of acceleration due to gravity?

A

9.81

6
Q

What is the formula for momentum?

A

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

7
Q

What is the formula for force?

A

Force (N) = mass x acceleration fma

m/s

8
Q

how to work out total distance?

A
```X = v{2}-u{2}/2a
x = total distance
a = acceleration```
9
Q

What is stopping distance equal to?

A

Stopping distance = thinking distance + braking distance

10
Q

What do the safety features in modern cars aim to do?

A

Absorb energy(crumple zones, slightly stretchy seatbelts)
reduce injuries
reduce the momentum to zero slowly, to reduce injuries

11
Q

What does the area under a speed time graph represent?

A

Distance

12
Q

What is the equation for acceleration?

A

(V-u)/time

13
Q

How do u calculate deceleration

A

Do the same as you would for acceleration and put a minus in front of the answer

14
Q

Energy efficiency equation

A

Useful energy output/total energy input X 100

15
Q

What is the name of he force which pushes back against the weight of an object

A

Lift

16
Q

How do you work out the moment of something?

A

force x perpendicular distance to the direction of force

17
Q

How to find the missing force on a lever (sea saw thing)

A
• label one side 1 and the other 2
• show force 1 x distance1 = force 2 x distance 2
• therefore force 1 (the unknown one) must equal force 2 x distance 2 divided by distance 1
18
Q

HOw do you work out the number of rotations (Gears)

A

driven/driver

19
Q

When will a body move in a circular motion?

A

When the direction of travel is at right angles to the centripetal force