Newton's Third Law
Answers
- What is the action
- reaction pair of forces acting on the airfoil as indicated by the
arrows? foil deflected upward and flow deflected
downward
- The weight force
is the product of the mass multiplied by the acceleration due to gravity.
If a DC-10 commercial passenger jet weighs 200,000 kilograms and gravity
is 9.80 m/s2, calculate the weight force: 1.96
x 106 N.
- If the DC-10 in
the previous question is flying at a constant altitude so that the action-
reaction forces are balanced, what is the lift force acting on the jet?
1.96 x 106 N
- As the jet in the
above question travels at constant velocity, it burns fuel, which decreases
its weight to 165,454 kg, a safe weight for landing. In response to
this decrease, what is the new lift force acting on the jet when altitude
is maintained? 1.62 x 106 N
- In a department
store, a large fan blows upward, keeping a beach ball at a constant
height above it. What exerts the action force on the beach ball? air
blown upward by fan
- In the example
above, what is the reaction force on the beach ball? weight
force exerted downward
- If the beach ball
above weighs 280 grams, what are the magnitude and direction of the
action force on the beach ball? 2.7 N upward
- When the fan blowing
on the beach ball above is turned off, how do the action and reaction
forces compare? unbalanced; there is no
longer a blowing force, just a weight force
- Once the beach
ball has landed on the ground, what exerts the action force? the
ground pushes up
the
reaction force? the ball pushes down
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