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Question

Physics Question on projectile motion

Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R
Assertion (A): The velocity of a projectile at a point on its trajectory is equal to the slope at that point.
Reason (R): The velocity vector at a point is always along the tangent to the trajectory at that point.
In the light of the above statements, choose the correct answer from the options given below

A

Both (A) and (R) are true and (R) is the collect explanation of (A)

B

Both (A) and (R) are true but (R) is not the con ect explanation of (A)

C

(A) is true but (R) is false

D

(A) is false but (R) is true

Answer

(A) is false but (R) is true

Explanation

Solution

Trajectory of a projectice is of form
y=f(x)=xtanθgx22u2cos2θy=f(x)=x \tan \theta-\frac{g x^{2}}{2 u^{2} \cos ^{2} \theta}
dydx=\therefore \frac{d y}{d x}= slope =dy/dtdx/dt=vyvx=\frac{d y / d t}{d x / d t}=\frac{v_{y}}{v_{x}}
So, Assertion (A) is incorrect.
Also, velocity of a projectile is always along tangent to the trajectory (shown)
Hence, reason (R)(R) is correct