A plane is inclined at an angle \(\alpha =30^\circ\) with respect to the horizontal. A particle is projected with a speed \(u=2~\text{ms}^{-1}\), from the base of the plane, making an angle \(\theta=15^\circ\) with respect to the plane as shown in the figure. the distance from the base, at which the particle hits the plane is close to: (Take \(g= 10\) ms–2)

      
1. \(14~\text{cm}\)
2. \(18~\text{cm}\)
3. \(20~\text{cm}\)
4. \(26~\text{cm}\)

Subtopic:  Projectile Motion |
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A shell is fired from a fixed artillery gun with an initial speed \(u\) such that it hits the target on the ground at a distance \(R\) from it. If \(t_1\) and \(t_2\) are the values of the time taken by it to hit the target in two possible ways, the product \(t_1t_2\) is:
1. \(\frac{2R}{g}\)
2. \(\frac{R}{2g}\)
3. \(\frac{R}{g}\)
4. \(\frac{R}{4g}\)

Subtopic:  Projectile Motion |
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The trajectory of a projectile near the surface of the earth is given as \(y=2x-9x^2\). If it were launched at an angle \(\theta_0\) with speed \(v_0\) then:\(\left(g= 10~\text{ms}^{-2}\right)\)

1. \(\theta_0=\cos^{-1}\left(\frac{1}{\sqrt{5}}\right) \text{ and }v_0=\frac{5}{3}~\text{ms}^{-1}\)
2. \(\theta_0=\cos^{-1}\left(\frac{2}{\sqrt{5}}\right) \text{ and }v_0=\frac{3}{5}~\text{ms}^{-1}\)
3. \(\theta_0=\sin^{-1}\left(\frac{2}{\sqrt{5}}\right) \text{ and }v_0=\frac{3}{5}~\text{ms}^{-1}\)
4. \(\theta_0=\sin^{-1}\left(\frac{1}{\sqrt{5}}\right) \text{ and }v_0=\frac{5}{3}~\text{ms}^{-1}\)
Subtopic:  Projectile Motion |
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Two particles are projected from the same point with the same speed \(u,\) but at different angles. They both cover the same horizontal range \(R,\) but reach different maximum heights, \(h_1\)​ and \(h_2.\) Which of the following relations is correct?
1. \(R^2=h_1h_2\)
2. \(R^2=16h_1h_2\)
3. \(R^2=4h_1h_2\)
4. \(R^2=2h_1h_2\)

Subtopic:  Projectile Motion |
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A helicopter rises from rest on the ground vertically upwards with a constant acceleration \(g\). A food packet is dropped from the helicopter when it is a height \(h\). The time taken by the packet to reach the ground is close to [\(g\) is the acceleration due to gravity]:
1. \( t=\sqrt{\frac{2 h}{3 g}} \)
2. \( t=1.8 \sqrt{\frac{h}{g}} \)
3. \( t=3.4 \sqrt{\left(\frac{h}{g}\right)} \)
4. \( t=\frac{2}{3} \sqrt{\left(\frac{h}{g}\right)}\)

Subtopic:  Projectile Motion |
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The trajectory of a projectile in a vertical plane is \(y=\alpha x-\beta x^2\), where \(\alpha\) and \(\beta\) are constants and \(x\) & \(y\) are respectively the horizontal and vertical distances of the projectile from the point of projection. The angle of projection \(\theta\) and the maximum height attained \(H\) are respectively given by :
1. \( \tan ^{-1} \alpha, \frac{\alpha^2}{4 \beta} \)
2. \( \tan ^{-1} \beta, \frac{\alpha^2}{2 \beta} \)
3. \( \tan ^{-1} \alpha, \frac{4 \alpha^2}{\beta} \)
4. \( \tan ^{-1}\left(\frac{\beta}{\alpha}\right), \frac{\alpha^2}{\beta} \)

Subtopic:  Projectile Motion |
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A projectile is projected with a velocity of 25 m/s at an angle \(\theta\) with the horizontal. After t seconds, its inclination with horizontal becomes zero. If R represents the horizontal range of the projectile, the value of \(\theta\) will be: [use g = 10 m/s2]
1.  \(\frac{1}{2} \sin ^{-1}\left(\frac{5 t^2}{4 R}\right) \)
2. \(\frac{1}{2} \sin ^{-1}\left(\frac{4 R}{5 t^2}\right) \)
3. \(\tan ^{-1}\left(\frac{4 \mathrm{t}^2}{5 \mathrm{R}}\right) \)
4. \(\cot ^{-1}\left(\frac{\mathrm{R}}{20 \mathrm{t}^2}\right)\)
Subtopic:  Projectile Motion |
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Given below are two statements: 
Assertion (A): Two identical balls A and B thrown with the same velocity ‘u’ at two different angles with horizontal attained the same range R. If A and B reached the maximum height h1 and h2 respectively, then \(\mathrm{R}=4 \sqrt{\mathrm{h}_1 \mathrm{~h}_2}\)
Reason (R): Product of said heights, 
\(\mathrm{h}_1 \mathrm{~h}_2=\left(\frac{\mathrm{u}^2 \sin ^2 \theta}{2 \mathrm{~g}}\right) \cdot\left(\frac{\mathrm{u}^2 \cos ^2 \theta}{2 \mathrm{~g}}\right)\)
 
1. Both (A) and (R) are true and (R) is the correct explanation of (A).
2. Both (A) and (R) are true but (R) is not the correct explanation of (A).
3. (A) is true but (R) is false.
4. (A) is false but (R) is true.
Subtopic:  Projectile Motion |
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A projectile is launched at an angle \('\alpha'\) with the horizontal with a velocity of 20 ms-1. After 10 s, its inclination with horizontal is \(' \beta'\). The value of \(tan \beta\) will be: (g = 10 ms-2)
1. \(\tan \alpha+5 \sec \alpha \)
2. \( \tan \alpha-5 \sec \alpha \)
3. \( 2 \tan \alpha-5 \sec \alpha \)
4. \(2 \tan \alpha+5 \sec \alpha\)
Subtopic:  Projectile Motion |
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A person can throw a ball up to a maximum range of \(100\) m. How high above the ground can he throw the same ball?
1. \(25\) m
2. \(50\) m
3. \(100\) m
4. \(200\) m
Subtopic:  Projectile Motion |
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