please solve this numerical. don't spam. class 9 physics
question no.6
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please solve this numerical. don't spam. class 9 physics
question no.6
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ANSWER IS 5 SECONDS.
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Given :
Unit conversion :
As per the requirement of the answer we need to convert the units of the given value.
We do know that to convert km/h into m/sec we need to multiply the given value by 5/18 therefore :
➞ Initial Velocity = [tex]\sf\:18 × 10⁴ × \frac{5}{18}[/tex]m/sec
➞ Initial Velocity = [tex]\sf\:\cancel{18} × \frac{5}{\cancel{18}} × 10⁴[/tex] m/sec
[tex]\sf\:\therefore[/tex] Initial Velocity = [tex]\sf\:5 × 10⁴[/tex]m/sec
To find :
Concept :
This type of questions can be solved by equation of motion. The equation of motions are as follows -
where ,
According the given clues in the question we would solve this numerical following First law of motion.
Solution :
Using First equation of motion -
[tex]\sf\:v=u+at[/tex]
As per the question ,
Substituting the values in the equation
[tex]\sf\dashrightarrow\:2u=u+at[/tex]
[tex]\sf\dashrightarrow\:2u-u=at[/tex]
[tex]\sf\dashrightarrow\:u=at[/tex]
[tex]\sf\dashrightarrow\:t=\frac{u}{a}[/tex]
[tex]\sf\dashrightarrow\:t=\frac{5\times10^{4}}{10^{4}}[/tex]
⠀⠀⠀⠀➻ using law of indices
[tex]\sf\dashrightarrow\:t=5 \times 10^{4-4}[/tex]
[tex]\sf\dashrightarrow\:t=5 \times 10^{0}[/tex]
[tex]\sf\dashrightarrow\:t=5 \times 1[/tex]
[tex]\small{\underline{\boxed{\mathrm{\dashrightarrow~t~=5~sec}}}}[/tex]
[tex]\bf\: Therefore~, [/tex]
⠀⠀⠀⠀⠀[tex]\bf\: Required~time~is~5~secs.[/tex]
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