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STATEMENT-1: A body is projected from th...

STATEMENT-1: A body is projected from the ground with a velocity v at an angle with the horizontal direction, it reaches a maximum height (H) and reaches the ground after a time T = 2u sin `theta//g`
STATEMENT-2: The vertical and horizontal motions can be treated independently

A

Statement-1 is True, Statement-2 is True, Statement -2 is a correct explanation for Statement-1

B

Statement-1 is True, Statement-2 is True, Statement -2 is NOT a correct explanation for Statement-1.

C

Statement - 1 is True, Statement-2 is False

D

Statement - 1 is False, Statement-2 is True.

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to analyze the motion of a projectile launched from the ground at an angle \(\theta\) with an initial velocity \(v\). We will derive the time of flight and discuss the independence of vertical and horizontal motions. ### Step-by-Step Solution: 1. **Understanding the Components of Motion:** - When a body is projected at an angle \(\theta\), its initial velocity \(v\) can be resolved into two components: - Horizontal component: \(v_x = v \cos \theta\) - Vertical component: \(v_y = v \sin \theta\) 2. **Time of Flight:** - The time of flight \(T\) for a projectile is the total time it takes for the projectile to return to the ground after being launched. - The vertical motion can be analyzed using the equation of motion: \[ S_y = v_y t - \frac{1}{2} g t^2 \] where \(S_y\) is the vertical displacement (which is 0 when it returns to the ground), \(v_y\) is the initial vertical velocity, \(g\) is the acceleration due to gravity, and \(t\) is the time of flight. - Setting \(S_y = 0\) gives: \[ 0 = v \sin \theta \cdot T - \frac{1}{2} g T^2 \] - Rearranging this equation leads to: \[ g T^2 = 2 v \sin \theta \cdot T \] - Dividing both sides by \(T\) (assuming \(T \neq 0\)): \[ g T = 2 v \sin \theta \] - Therefore, the time of flight \(T\) is: \[ T = \frac{2 v \sin \theta}{g} \] 3. **Maximum Height:** - The maximum height \(H\) can be calculated using the vertical motion equations. At maximum height, the vertical velocity becomes zero. - Using the equation: \[ v_y^2 = u_y^2 - 2gH \] where \(v_y = 0\) at maximum height, we have: \[ 0 = (v \sin \theta)^2 - 2gH \] - Rearranging gives: \[ H = \frac{(v \sin \theta)^2}{2g} \] 4. **Independence of Motion:** - The horizontal motion is uniform, as there is no acceleration in the horizontal direction (ignoring air resistance). The horizontal distance traveled can be calculated as: \[ S_x = v_x \cdot T = (v \cos \theta) \cdot T \] - The vertical and horizontal motions can be treated independently because the horizontal motion does not affect the vertical motion and vice versa. ### Conclusion: - **Statement-1** is true: The time of flight \(T = \frac{2v \sin \theta}{g}\) is correct. - **Statement-2** is also true: The vertical and horizontal motions can indeed be treated independently.
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