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# phy(ticker tape timer)

一條紙帶連接ticker tape timer由手推車沿斜板滑下,

然後剪出三部分,而三部分是連續的,每部分有5點,

第一部分4cm,第二部分6cm,第三部分8cm。

如ticker tape timer每秒打出50點,

what is the uniform acceleration of the 手推車?

答案係2ms^-2

please tell me點計and寫出算式please!!

### 1 Answer

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- Gabriella MontezLv 71 decade agoFavorite Answer
Time required to produce 1 dot = 1 / 50 = 0.02s

Since there're 5 dots in each tape, the time interval is:

0.02 x 5 = 0.1s

Average speed of the trolley in the 1st interval:

4 / 0. 1 = 0.4 m / s

Average speed of the trolley in the 2nd interval:

6 / 0. 1 = 0.6 m / s

Average speed of the trolley in the 3rd interval:

8 / 0.1 = 0.8 m / s

Then,

v = u + at

0.8 = 0.4 + a ( 0.1 x 3 - 0.05 - 0.05 )

0.4 = 0.2a

a = 2m/s2 which is the uniform acceleration of the trolley

Source(s): My Phy Knowledge

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