Kinetics Flashcards
Equation for distance
Average speed x time
Five equations of motion
V = u + at S = (u + v) t / 2 S = Ut + 1/2 at2 V2 = u2 + 2as H = Ut + 1/2 gt2
Define acceleration
Change in speed over time
What is the number for gravity
9.81
What is centripetal force?
When the acceleration is going in the same direction as the force.
Constant change in direction, constant acceleration
Formula for centripetal force?
Mass x Velocity2 / Radius
Formula for centripetal acceleration
Velocity squared / radius
What is vibration
Mechanical oscillations about an equilibrium point
What is free vibration.
A mechanical system set off with an original input then allowed to vibrate freely
What is forced vibration
Alternating force is applied to a mechanical system.
E.g washing machine
What is resonance
The tendency of a system to oscillate at maximum amplitude at a certain frequency.
What is velocity ratio?
Mechanical advantage. The ratio of effort for loading movement
What is the equation for velocity ratio.
Distance moved by effort / distance moved by load
How is mechanical advantage calculated ?
Resistance / Effort
What are the two types of mechanical advantage
Actual mechanical advantage
Ideal mechanical advantage
What is actual mechanical advantage
Ratio of output force to input force.
Fo / F1
What is ideal mechanical advantage
Would exist if there was no friction in the machine.
D1/ Do
Ratio of input distance to output distance
Formula for work
Work = f x d
Example of class 1 lever
Seesaw
Example of class 2 lever
Wheelbarrow
Difference between class 1 and class 2 lever
The resistance and effort on class 2 move in the same direction
Example of class 3 lever
Aircraft landing gear
What are inclined planes
Another way to gain mechanical advantage.
E.g ramp
What are spur gears
Used to connect two parallel shafts
What are bevel gears
When the drive shaft and rivet shaft are not parallel
What are worm gears
Needed when an extreme amount of mechanical advantage is needed. Spiral ridge around a shaft for the drive gear.
What are planetary gear systems
Reduce the propeller shaft speed on mor powerful aircraft engines.
How do we calculate efficiency
Using mechanical advantage.
Work output / work input x 100%
