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SteamboatsQuiz at Nine
Posted on November 27th, 2009 by James Higham
1. A golf ball moving through air experiences two major aerodynamic forces, ____ and ____, as does an aircraft wing or a sail.
Incidentally, Wiki say:
Golfers can wash their balls manually, but there are also mechanical ball washers available.
Ooo, I feel faint already.
2. What’s the name of the course where the balls run around in a ball bearing mechanism?
3. A gimme – the Latin “Testis unus, testis nullus” gave the name to which human glands?
4. What is the formula for finding the volume of a sphere?
5. What mathematical shape is closest to a rugby ball?
Answers
Lift & drag, race, testicles, four over three pi ar cubed, ovoid
Filed under: Diversions
hmm 3/5
Oooh this is a bit below the belt, James.
BTW, the Higgs bosun has just been discovered in a Southampton pub where he was hiding in a cellar cask.
4/5
QI Supposedly to testify or give testimony is to actually swear by ones bollocks, as in “may my bollocks be removed if I give false witness.”
Wether any gonads were actually ever removed is a matter of debate.
(Women obviously were not allowed to give evidence and the evidence of slaves was only admissable if obtained or confirmed after torture)
Mmm! 3/5 I am not sure I should own up to that score, it is higher than usual!!!
3.5/5. Didn’t know the race one and got the ball one different. As usual I disagree on the golf ball one. Golf balls are not subject to lift and drag but gravity and drag. It’s the initial velocity that gives them the lift and their ballistic trajectory but it bleeds off due to gravity and drag. Thats why bricks, etc follow the same trajectories and they don’t claim to have lift.
A golf ball spinning about a vertical axis can also be subject to a sideways force which you can only call “lift” by abusing the plain English meaning of “lift”, implying verticality. If you make them spin about a horizontal axis they presumably can also be subject to “lift”, whatever the good lord says.
When a golf ball is hit, the impact, lasting less than a microsecond, determines the ball’s velocity, launch angle and spin rate, all of which influence the its trajectory (and its behavior when it hits the ground).
A ball moving through air experiences two major forces: lift and drag. Drag slows the forward motion, whereas lift acts in a direction perpendicular to it. The magnitude of these forces depends on the behavior of the boundary layerThe boundary layer is the layer of fluid in the immediate vicinity of a bounding surface. In the atmosphere the boundary layer is the air layer near the ground affected by diurnal heat, moisture or momentum transfer to or from the surface. On an aircraft of air moving with the ball surface.
Every modern golf ball has dimples; their purpose is to increase and shape the lift and drag forces by modifying the behavior of the boundary layer. It should be noted that drag and lift forces exist also on smooth balls: they are only modified, not created, by dimples.
One effect of dimples is a reduction of drag, contributing to the increased length of flight of dimpled balls compared with smooth ones.
A spinning ball deforms the flow of air around it, thus acting similar to an airplane wing. Backspin is imparted in almost every shot due to the golf club’s loft (i.e. angle between the clubface and a vertical plane). A backspinning ball experiences an upward lift force which makes it fly higher and longer than a ball without spin would. Sidespin occurs when the clubface is not aligned perpendicularly to the direction of swing, leading to a lift force that makes the ball curve to a side. These lift forces are further increased through the presence of dimples.
I stand corrected.
The thing is – you’re right too! The article failed to mention your points.
Perhaps but it did say aerodynamic forces. Gravity is not an aerodynamic force but drag and lift are. As the question was phrased I was incorrect. My bad for not getting that straight away.