Speed

[Guest]

Try this one:

A motorcycle was used to clock a baseball in 1940. The motorcycle passed the pitcher as he was starting the windup. The motorcycle had a 10 feet head start. The baseball won by 3 feet.

Speed of motorcycle- 86 mph.

Calculate speed of baseball.

[Guest]

In 1940 they had motorcycles with speedometers..??..so the motorcyclist knew how fast he was going..??..and did no one else know....??
....but they didn't have a device to know how fast a ball was travelling..??
It would have probably been easier to try to measure the ball speed directly rather than try to figure out when the pitcher started, when the motorcycle started, which was going faster and when each finished...etc...etc....and then still have to work it out...???..
..........was the motorcycle just used as a big stopwatch....??

I don't know anything about baseball but for the question I would have thought they could have at least measured the distance travelled under test with a simple tape measure or what was available at that time.......??

The pitching distance doesn't seem to be standard either.....??

Here are some pitching distances I got when googled the internet:

Little League pitching distance - 46 feet

Pony League pitching distance - 54 feet

Babe Ruth league pitching distance - 60 feet, 6 inches

High school pitching distance - 60 feet, 6 inches

College pitching distance - 60 feet, 6 inches

Professional pitching distance - 60 feet, 6 inches


So for the question I will take the pitching distance to be 60.5 feet....and the motorcycle has constant speed 86 mph throughout.
Once the pitcher lets go of the ball it travels at constant speed with negligable air resistance.
The pitcher winds up as the motorcycle (at 86mph) passes him, pitcher then pitches (at time t=0) by which time the motorcycle has travelled 10 feet.
Both travel at constant speed and some time later the ball passes the motorcycle. The ball and motocycle continue travelling until the ball is hit by the batter at the end of the distance, at which time the motorcycle is 3 feet behind.

For the test the motorcycle travels ( 60.5 - 13 ) = 47.5 feet in the same time as the ball travels 60.5 feet.

86 mph = 86 x 5280 /3600 = 126.133 feet per second

Time taken for test = 47.5 / 126.133 = 0.3766 seconds

Speed of ball = 60.5 / 0.3766 = 160.6479 feet per second = 109.5327 mph.


.....................Simple................

[Guest]

I conducted some research and found:

Location- Lincoln Park in Chicago, Illinois., Professional Baseball- 60.5 feet distance.

Pitcher- Bob Feller, Cleveland Indians.

Required to hit a target 12 inches in diameter.

Harley-Davidson Police Motorcycle.

The pitch was recorded to be 98.6 mph at the time, but was later calculated to be 104 by updated measuring methods.

According to data in the problem, the answer would be "mathematically" correct.

[Guest]

OK
Which answer is correct, 98.6 or 104 or 109.5 ?
How do you solve it with only the data given in the question?.
Do we not need to know either the total time for the test or the total distance?.

Interesting "updated measuring methods". I assume at sometime later. Must be measured from recordings.
Maybe introduced even more variables?

[Guest]

More research:

From a later interview- In 1946 a photo-electric device used by the Army to test weapons timed Feller's speed at 98.6 mph. He said that was "terminal velocity". In the 1940 motorcycle test, he said it worked out to 104.

By the numbers in the problem ( 60.6 feet, 86 mph, head start of 10 feet, baseball winning by 3 feet), your solution would by "mathematically" correct. I don't know how he said it was 104.

[Guest]

Error in my last post:

Should be 60.5 feet instead of 60.6 feet.

[Guest]

I googled a bit more myself and found a video clip of the test on www.efastball.com
From the original video they should know the frames per second they were shooting at and should be able to calculate from that and forget about the motorcycle. The video in reality should only last about 0.4 seconds but should have all the frames.

When the ball is in flight it will be subject to drag etc from the air etc. which will slow it down also forces of gravity which will cause the path to "droop"

The vertical drop due to gravity (assuming ideal) s = 0.3gt^2
In metric units roughly s = 0.5 x 9.81 x 0.4 x 0.4 = 0.75 metres roughly.
From the video it doesn't look as much as that, probably about half of that.
Suggests maybe the speed is even faster..........

[Guest]

I decided I would google "High Speed Photography" and came across the following in Wikipedia.....

The first practical application of high-speed photography was Eadweard Muybridge's 1878 investigation into whether horses' feet were actually all off the ground at once during a gallop. The first photograph of a supersonic flying bullet was taken by the Austrian physicist Peter Salcher in Rijeka in 1886, a technique that was later used by Ernst Mach in his studies of supersonic motion.[1] German weapons scientists applied the techniques in 1916.

They were able to take film photography at hundreds of frames per second in 1886, so I dont think there is much excuse for using a motorcycle as a stopwatch in 1940 and some form of low speed photography and also not be able to calculate the speed acurately. All they would have had to do is count the frames on the film.....

............................Simple................................