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Jobisdone [24]
3 years ago
5

Ask Your Teacher A 51-kg pole vaulter running at 11 m/s vaults over the bar. Her speed when she is above the bar is 1.1 m/s. Neg

lect air resistance, as well as any energy absorbed by the pole, and determine her altitude as she crosses the bar.
Physics
1 answer:
Tanzania [10]3 years ago
7 0

Answer:

6.11 N

Explanation:

Let,

m= mass of vaulter

Vi initial speed =11 m/s

Vf speed on pole (final) =1.1 m/s

Yi = initial height (when on ground)=o m

Yf = Height while crossing the pole =?

This problem can be solved by using conservation of energy rule;

KEi + PEi = KEf + PEf

==> 1/2 mVi^{2}+ mg Yi_{} = 1/2 m Vf^{2}+mgYf_{}

Initially the altitude of vaulter is zero i-e Yi=0_{} ==> PEi = mg Yi_{}= mg×0=0

==>1/2 mVi^{2}= /2 m Vf^{2}+mgYf_{}

==> mVi^{2}=m Vf^{2}+2mgYf_{}

cancelling m

==> Vi^{2}= Vf^{2}+2gYf_{}

==> Vi^{2}- Vf^{2}=2gYf_{}

==> Yf_{}=\frac{Vi^{2}-Vf^{2}   }{2g}

==> = =\frac{11^{2 }-1.1^{2}  }{2 (9.8)}

==>  Yf_{}==\frac{119.79}{19.6}=6.11N

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Answer and Explanation:

Data provided in the question

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Answer:

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