Mechanical, Physics & Science Flashcards
What are Newton’s three laws of motion?
- Inertia
- Acceleration
- Action/Reaction
What is the Bernoulli Principle?
Bernoulli’s Principle states that faster moving air has low air pressure and slower moving air has high air pressure. The difference in air pressure cause lift.
How does the Bernoulli Principle correlate with the Airspeed Indicator (ASI)?
It’s used to calibrate the airspeed indicator (ASI) so that it displays the indicated airspeed appropriate to the dynamic pressure.
Who is Daniel Bernoulli?
A Swiss mathematician and physicist
What is Newton’s 1st law of motion (Inertia)?
An object at rest tends to remain at rest. An object in motion tends to remain in motion unless acted upon by an outside force.
What is Newton’s 2nd law of motion (Acceleration)?
Force applied to overcome inertia of an object. The greater the mass of the object the greater force required to produce a particular acceleration.
What is Newton’s 3rd law of motion (Action/Reaction)?
For every action there is an equal or opposite reaction.
What are four forces that act upon an aircraft in flight?
- Lift
- Gravity (aka weight)
- Thrust
- Drag
Our atmosphere is composed of what?
78 percent Nitrogen; 21 percent Oxygen; 1 percent other gas elements (i.e. argon, helium)
What is the weight of the atmosphere at sea level?
14.7 pounds
Which air is denser? Warm or cold?
Warmer air is less dense that cooler air; produces less lift.
How is Newton’s 2nd Law of Motion calculated?
Force = Mass x Acceleration
What is centripetal force?
Center seeking force
What is centrifuged force?
Acts opposite to centripetal force and helps maintain tension
What is gravity?
Pull of the earth on all bodies on earth
What is the mass of the earth?
6 x 10^24 kg
What is the force or pull of earth?
9.8 N
How is weight calculated?
Weight = Mass x acceleration due to gravity
What unit of measure for mass and weight?
Mass = Kilograms Weight = Newton
What is Center of Gravity?
Point of a body through which the weight of the body acts
What is torque?
Product of force and moment arm. Causes rotation of a body about a point called the pivot or fulcrum.
What is torque calculated?
Torque = Force x perpendicular distance from the pivot
Without friction what happens?
A body moving with uniform velocity will continue moving with the same velocity until stopped by an external force.
What are the two types of friction?
Static & Kinetic
What is static friction?
Friction applied by a body at rest in friction to a force attempting to move it.
What is kinetic friction?
Once a body is set in motion and no longer experiences static friction.
What is the law of conservation of energy?
Energy can neither be created, nor be destroyed, but it can only change from one form to another.
One joule is equal to what?
1 Nm
How is Potential Energy calculated?
Potential Energy = mass x acceleration due to gravity x height = mgh
How is kinetic energy calculated?
Kinetic Energy = 1/2 x mass x (velocity of the body)^2 = 1/2mv^2
How is work done calculated?
Work done = Force x displacement
How is Power as it relates to rate of work done calculated?
Power = work done / time taken
What unit of measure does power use?
Watt (w); equal to Joule/s. Other units of power are: Horsepower and foot-pound per second (ftlb/s)
What does 1 horsepower equal?
550 ftlb/s (or) 746J/s = 746 W
If no work is done, what is the power?
0
How is mechanical advantage calculated?
Mechanical advantage = output force / input force
What are three mechanical bodies?
- Input arm
- Fulcrum/pivot
- Output arm
What is a first class lever?
Have a pivot in the center and the input/output arms on either side
What is a second class lever?
Have the output force, or load, between the fulcrum and the input force
What is a third class lever?
Have the input force acting between the fulcrum and the output load
How is the mechanical advantage of Wedges calculated?
Length of Wedge / Thickness across the Wedge
How is the mechanical advantage of Pulleys calculated?
Input force / Output force
How is the mechanical advantage of Wheels and Axles calculated?
Radius of Wheel / Radius of Axle
How is the mechanical advantage of Gears calculated?
Radius of Output Wheel / Radius of Input Wheel
What happens when a gear arrangement has a mechanical advantage of 2?
The output gear has a radius double the input wheel, and it rotates once for every two rotations of the input wheel.
What is the unit of measure for pressure?
Pascals (Pa), pounds per square inch (psi), Newton per square meter (N/m^2), or inches of Mercury (inHg).
How is the mechanical advantage of Hydraulic Pressure Transmission calculated?
Area of the output piston / Area of the input piston
What does a piston mechanical advantage of 2 mean?
The area of the output piston is double the area of the input piston, but moves 1/2 the distance of the input piston.
