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**mathland****Banned**- Registered: 2021-03-25
- Posts: 438

At a certain instant, the speedometer of an automobile

reads V mi/h. During the next 1/4 s the automobile travels 20 ft.

Estimate V from this information.

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**Bob****Administrator**- Registered: 2010-06-20
- Posts: 9,128

speed = distance / time

B

Children are not defined by school ...........The Fonz

You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei

Sometimes I deliberately make mistakes, just to test you! …………….Bob

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**mathland****Banned**- Registered: 2021-03-25
- Posts: 438

Bob wrote:

speed = distance / time

B

At a certain instant, the speedometer of an automobile

reads V mi/h. During the next 1/4 s the automobile travels 20 ft.

Estimate V from this information.

Distance = 20 feet

Time = (1/4)s

Is the formula V = 20/(1/4)s miles per hour?

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**Bob****Administrator**- Registered: 2010-06-20
- Posts: 9,128

Arh! Good question.

The units for V are determined by what units are used for D and T. So if you do 20/0.25 you have the velocity in ft / s.

To get an answer in mph you'll have to do the conversions.

20 ft converts to 20/(3 x 1760) miles and 0.25 s converts to 0.25/3600 hours.

Bob

Children are not defined by school ...........The Fonz

You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei

Sometimes I deliberately make mistakes, just to test you! …………….Bob

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**mathland****Banned**- Registered: 2021-03-25
- Posts: 438

Bob wrote:

Arh! Good question.

The units for V are determined by what units are used for D and T. So if you do 20/0.25 you have the velocity in ft / s.

To get an answer in mph you'll have to do the conversions.

20 ft converts to 20/(3 x 1760) miles and 0.25 s converts to 0.25/3600 hours.

Bob

Very good. Not too bad. Interesting question.

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