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Triss [41]
3 years ago
14

A ball is dropped and falls with an acceleration of 9.8m/s2 downward. it hit the ground with a velocity of 49 m/s downward. how

long did it take the ball to fall to the ground?
Physics
1 answer:
Lelechka [254]3 years ago
4 0
V=u+at
49=0+9.8t
t=49/9.8
t = 5 (seconds)

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2 years ago
What types of galaxies are these?
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the first one looks like a spiral galixy

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2 years ago
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10. A 12 kg load hangs from one end of a rope that passes over a small frictionless pulley. A 15 kg counterweight is suspended f
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3 years ago
The rate at which a metal alloy oxidizes in an oxygen-containing atmosphere is a typical example of the practical utility of the
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Answer:

The activation energy is  Q = 328.31 \ K J/mol

Explanation:

From the question we are told that

      The rate constant is  k

       at the temperature T_1  = 300 =  300 + 273 =  573 \ K

      The value of k is  k_1 = 1.05 *10^{-8} \  kg /m^4 \cdot s

      at temperature T_2 = 400 ^oC =  400 + 273 =  673 \ K

       The value of  k is  k_2 = 2.95 *10^{-4} \ kg /m^4 \cdot s

The rate constant is mathematically represented as

       k  =  Ce^{- \frac{Q}{RT} }

Where Q is the activation energy

         R is the ideal gas constant with a value of  R =  8.314 \ J /mol \cdot K

          C is a constant

           T is the temperature

For the first  rate constant

       k_1 = Ce ^{-\frac{Q}{RT_1} }

For the second   rate constant

       k_2 = Ce ^{-\frac{Q}{RT_2} }

Now the ratio between the two given rate constant is  

      \frac{k_1 }{k_2}  =  e^{(\frac{Q}{R} [\frac{1}{\frac{T_2 - 1}{T_1} } ] )}

  =>    ln [\frac{k_1}{k_2} ] =  \frac{Q}{R}  * [\frac{1}{\frac{T_2 -1}{T_1} } ]

substituting values  

       ln [\frac{1.05 *10^{-8}}{2.95 *10^{-4}} ] =  \frac{Q}{8.314}  * [\frac{1}{\frac{673 -1}{573} } ]

=>     Q = 328.31 \ K J/mol

7 0
3 years ago
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