# P2.1 + 2 Forces and Their Effects + Kinetic Energy Flashcards

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1
Q

What factors affect thinking distance?

A

Drugs e.g caffeine and alcohol

Tiredness

2
Q

What is the thinking distance?

A

The distance the vehicle travels under the driver’s reaction time.

3
Q

What effect does the size of the parachute have on terminal velocity?

A

Bigger parachute = bigger resistance = faster time to reach terminal velocity = slower terminal velocity

4
Q

What is the breaking distance?

A

The distance a vehicle travels under the breaking force.

5
Q

What affects the breaking distance?

A
• Speed
• Condition of brakes
• Condition of tyres
6
Q

What is momentum?

A

A property of moving objects

7
Q

What is the relationship between

mass + velocity and momentum?

A

+ mass = + momentum

+ velocity = + momentum

8
Q

What is the law of conservation of momentum?

A

In a closed system (no outside forces) the total momentum is the same before an event as after it.

9
Q

Describe terminal velocity

A
• Forces unbalanced (gravity > frictional force)
• Causes acceleration
• Speed increases = More particles/second hit = resistance increases
• The amount of speed = the amount of resistance eventually
• Constant speed in the same direction means terminal velocity has been reached
10
Q

What is the relationship between force and momentum?

A

A force acting on an object causes a change in momentum.
increased force = faster momentum change =
increased acceleration

11
Q

Explain a car’s safety features using momentum.

A

They slow down people over a longer time - a slower change in momentum means a smaller force acting on them and less damage.

12
Q

What is an elastic object?

A

An object that can return to its original shape after the force that changed it is removed.

13
Q

How does an elastic object go back to its original shape?

A
• Work is done (kinetic energy transferred) to an elastic to change its shape.
• This is stored as elastic energy in the object.
• After the force is removed, this is converted back into kinetic energy
14
Q

What is the relationship between the load and spring extension?

A

They are directionally proportional up to the limit of proportionality.

15
Q

What is the limit of proportionality?

A

The maximum force an elastic object can take and still extend proportionally.

16
Q

What is velocity?

A

Speed in a given direction.

17
Q

How do you calculate distance from a velocity graph?

A

The area under the graph.

18
Q

What does acceleration, steady speed and deceleration look like on a velocity graph?

A

/ = acceleration

curved / = increasing acceleration

\ = deceleration

curved \ = decreasing acceleration

19
Q

What does acceleration, steady speed, stop and deceleration look like on a distance time graph?

A

steepening curve / = acceleration

levelling off curve / = deceleration

— = stopped

20
Q

How is resultant force calculated?

A

Forces in the same direction are added
Forces in opposite directions are subtracted.
Whichever distance has the greatest force is the one the object moves in.

21
Q

What happens when there is a zero resultant force?

A

Equilibrium.

The object does not accelerate - if already moving than carries on at the same speed or if still doesn’t move.

22
Q

What does a non zero resultant force mean?

A

The object will accelerate.

23
Q

What is the rule of forces for when two objects interact?

A

For every force exerted there is an equal and opposite one.