Kinematics Question 466
Question: Assertion: When range of a projectile is maximum, it’s angle of projection may be 45° or 135°. Reason: Whether q is 45° or 135°, value of range remains the same, only the sign changes.
Options:
A) If both assertion and reason are true and the reason is the correct explanation of the assertion.
B) If both assertion and reason are true but reason is not the correct explanation of the assertion.
C) If assertion is true but reason is false.
D) If the assertion and reason both are false.
E) If assertion is false but reason is true.
Show Answer
Answer:
Correct Answer: A
Solution:
Range, $ R=\frac{u^{2}\sin 2\theta }{g} $ when $ \theta =45^{o}, $
$ {R _{\max }}=\frac{u^{2}}{g}\sin 90^{o}=\frac{u^{2}}{g} $ when $ \theta =135^{o}, $
$ {R _{\max }}=\frac{u^{2}}{g}\sin 270^{o}=\frac{-u^{2}}{g} $ Negative sign shows opposite direction.
