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Motion In A Plane

Question
CBSEENPH11020302

A boy can throw a stone up to a maximum height of 10 m. The maximum horizontal distance that the boy can throw the same stone up to will be

  • 20 square root of 2m
  • 10 m

  • 10 square root of 2 m
  • 20 m

Solution

D.

20 m

Maximum speed with which the boy can throw stone is
straight u space equals space square root of 2 gh end root
space equals space square root of 2 space straight x 10 straight x 10 end root
space equals 10 square root of 2 space straight m divided by straight s
Range is maximum when projectile is thrown at angle of 45o, Thus,
straight R subscript max space equals space fraction numerator straight u squared over denominator straight g space end fraction space equals space fraction numerator left parenthesis 10 square root of 2 right parenthesis squared over denominator 10 end fraction space equals space 20 space straight m