Motion And Forces Flashcards
What is the equation for momentum?
Momentum = Mass x Velocity
p = m x v
What is the equation for force?
Force = Change in momentum / Time taken for change
F = mv - mu / t
Or
F = m (v - u) / t
What is Newton’s third law?
For every action there is an equal and opposite reaction
What factors can after drivers reaction times?
- Tiredness
- Alcohol and drug use
- Distractions
- Age
What is human reaction time?
The time between a stimulus occurring and a response
What factors affect the braking distance?
- Icy or wet road
- Worn brakes or tires
- Mass of the car
What does the slope of a velocity/time graph tell you?
Acceleration
What does the area under a velocity/time graph tell you?
Distance travelled
What is the typical speed of walking?
1.5 m/s
What is the typical speed of running?
3 m/s
What is the typical speed of cycling?
6 m/s
What is the typical speed of driving?
13-30 m/s
What is the typical speed of sound in air?
330 m/s

What is Newton’s first law?
A body will remain at rest or continue in a straight line at a constant speed as long as the force acting on it are balanced
What is newton second law?
Resultant force = mass x acceleration
What is acceleration in freefall?
10 m/s^2
What is inertial mass?
A measure of how difficult it is to change the velocity of an object
How do you define inertial mass?
The ratio of force over acceleration
How can you measure human reaction time?
- Ruler drop test
- Metre ruler is held vertically, level with a persons finger and thumb
- The ruler is dropped and grasped by person
- They record the length they caught it at
