Question

Assertion When $\theta =45^{\circ }$ or $135^{\circ }$, the value of $R$ remains the same, only the sign changes.
Reason $R=\frac{u^2\sin 2\theta }{g}$

• A. Both assertion and reason are true and reason is the correct explanation of assertion
• B. Both assertion and reason are true but reason is not the correct explanation of assertion
• C. Assertion is true but reason is false.
• D. Both assertion and reason are false.

Answer 1

Answer: (A)

Horizontal range $=\frac{u^2\sin 2\theta }{g}$
When $\theta =45^{\circ }$, maximum horizontal range
$R_{\max }=\frac{u^2}{g}\sin 90^{\circ }=\frac{u^2}{g}$
When $\theta =135$, maximum horizontal range
$R=\frac{u^2}{g}\sin 270=\frac{-u^2}{g}$
Negative sign implies opposite direction.