Unit 2 - Forces Flashcards
Name 5 forces?
- Gravity
- Friction
- Thrust
- Reaction
- Resistance
What can forces do?
- Puush
- Pull
- Turn
- Change
- Twist
The direction of an object
What unit do forces use?
Newtons
If an unbalanced force acts upon an object, what will change?
It’s motion
If no resultant force acts upon an object, what will happen to the object?
The object will either remain** stationary** or **continue moving **at a constant velocity
Veloctiy
Speed in a given direction
Resultant Force
The overall force on an object
What’s the equation for force?
Force = mass x acceleration
What does every reaction have?
An equal and opposite reaction
What is the equation for Velocity?
Velocity = distance ÷ time
What is the equation for acceleration?
Acceleration = (final velocity - start velocity) ÷ time
What is the equation for weight?
Weight = mass x gravitational field strength
Thinking time
The time take or an individual to decide weather to stop or not
Thinking Distance
The distance moved during the time when you are reacting to a hazard
Braking Time
The time for the car to slow down
Braking distance
The distance travelled whilst braking
Factors affecting thinking distance?
- Tiredness
- Alcohol
- Drugs
- Distractions eg loud music, phone
Factors affecting braking distance?
- How worn the brakes are
- Tyres
- Surface of the road
- Mass of the vehicle
- Aerodynamics
What is the Overall Stopping Distance?
The thinking distance and the braking distance added together
Air resistance
A force due to air that is acting to oppose the motion of an object
Factors affecting the size of air resistance?
- Surface area
- Speed of an object
Regenetarive braking
An energy recovery mechanism which slows a vehicle or object down by converting its kinetic energy into another form which can be stored.
Uses of Regenetarive braking?
- Trains
- KERS (kinetic energy recover systems) in formula 1
Problems with regenetarive braking?
- Makes turning harder
- Less predictable when turning
- Cars still need friction
Equation for work done?
Work done = energy transferred
**Work done = force x distance moved **
(in the direction of the force)
Name 4 ways you can reduce frictionq
- Lubrication (with oil, this means the surfaces no longer rub directly on each other, but slide past on a layer of oil)
- Air (eg ice hockey, there’s no friction to slow it down)
- Ball/roller bearings (where balls or rollers allow the surface to move easily without actually touching each other)
- Using special materials (eg Teflon, which have a very low co-efficiant of friction and this slide easily)
