Home
Class 12
PHYSICS
A body A is thrown up vertically from th...

A body A is thrown up vertically from the ground with velocity `V_(0)` and another body B is simultaneously dropped from a height H. They meet simultaneously dropped from a height H. They meet at a height `(H)/(2)` if `V_(0)` is equal to

A

`sqrt(2gH)`

B

`sqrt(gH)`

C

`(1)/(2)sqrt(gH)`

D

`sqrt((2g)/(H))`

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to find the initial velocity \( V_0 \) of body A, which is thrown upwards from the ground, such that it meets body B, which is dropped from a height \( H \), at a height of \( \frac{H}{2} \). ### Step-by-Step Solution: 1. **Understand the Motion of Body A (Thrown Upwards)**: - Body A is thrown upwards with an initial velocity \( V_0 \). - The height \( y_A \) of body A after time \( t \) can be expressed using the equation of motion: \[ y_A = V_0 t - \frac{1}{2} g t^2 \] - Here, \( g \) is the acceleration due to gravity (approximately \( 9.81 \, \text{m/s}^2 \)). 2. **Understand the Motion of Body B (Dropped Downwards)**: - Body B is dropped from a height \( H \) with an initial velocity of \( 0 \). - The height \( y_B \) of body B after time \( t \) can be expressed as: \[ y_B = H - \frac{1}{2} g t^2 \] 3. **Set Up the Equation for Meeting Point**: - The bodies meet at a height of \( \frac{H}{2} \). Therefore, we can set the heights equal: \[ y_A = y_B = \frac{H}{2} \] 4. **Substituting for Body A**: - Substitute \( y_A \) into the equation: \[ \frac{H}{2} = V_0 t - \frac{1}{2} g t^2 \quad \text{(1)} \] 5. **Substituting for Body B**: - Substitute \( y_B \) into the equation: \[ \frac{H}{2} = H - \frac{1}{2} g t^2 \] - Rearranging gives: \[ \frac{1}{2} g t^2 = H - \frac{H}{2} = \frac{H}{2} \] - Thus, we have: \[ g t^2 = H \quad \text{(2)} \] 6. **Solving for Time \( t \)**: - From equation (2): \[ t^2 = \frac{H}{g} \quad \Rightarrow \quad t = \sqrt{\frac{H}{g}} \] 7. **Substituting \( t \) back into Equation (1)**: - Substitute \( t \) into equation (1): \[ \frac{H}{2} = V_0 \sqrt{\frac{H}{g}} - \frac{1}{2} g \left(\sqrt{\frac{H}{g}}\right)^2 \] - Simplifying gives: \[ \frac{H}{2} = V_0 \sqrt{\frac{H}{g}} - \frac{1}{2} g \cdot \frac{H}{g} \] - This simplifies to: \[ \frac{H}{2} = V_0 \sqrt{\frac{H}{g}} - \frac{H}{2} \] 8. **Rearranging to Solve for \( V_0 \)**: - Adding \( \frac{H}{2} \) to both sides: \[ H = V_0 \sqrt{\frac{H}{g}} \] - Dividing both sides by \( \sqrt{\frac{H}{g}} \): \[ V_0 = \frac{H}{\sqrt{\frac{H}{g}}} = \sqrt{gH} \] ### Final Answer: The value of \( V_0 \) is: \[ V_0 = \sqrt{gH} \, \text{m/s} \]

To solve the problem, we need to find the initial velocity \( V_0 \) of body A, which is thrown upwards from the ground, such that it meets body B, which is dropped from a height \( H \), at a height of \( \frac{H}{2} \). ### Step-by-Step Solution: 1. **Understand the Motion of Body A (Thrown Upwards)**: - Body A is thrown upwards with an initial velocity \( V_0 \). - The height \( y_A \) of body A after time \( t \) can be expressed using the equation of motion: \[ ...
Promotional Banner

Topper's Solved these Questions

  • MOTION IN A PALNE

    ALLEN|Exercise EXERCISE-2|170 Videos
  • MOTION IN A PALNE

    ALLEN|Exercise EXERCISE-3|41 Videos
  • MOTION IN A PALNE

    ALLEN|Exercise SOLVED EXAMPLE|28 Videos
  • KINEMATICS-2D

    ALLEN|Exercise Exercise (O-2)|48 Videos
  • NEWTON'S LAWS OF MOTION & FRICTION

    ALLEN|Exercise EXERCISE (JA)|4 Videos

Similar Questions

Explore conceptually related problems

A body is dropped from a certain height.

A body is dropped vertically from a certain height. Draw velocity time graph of the body.

A body A is thrown vertically upwards with initial velocity v_(1) . Another body B is dropped from a height h. Find how the distance x between the bodies depends on the time t if the bodies begin to move simultaneously.

A body is just dropped from a height. What is its initial velocity?

A body is dropped from a height H. The time taken to cover second half of the journey is

A ball is thrown vertically upwards from the top of tower of height h with velocity v . The ball strikes the ground after time.

A body is projected vertically up from ground with a velocity u so as to reach maximum height 'h'. At half of the maximum height its velocity will be

A body A of mass 4 kg is dropped from a height of 100 m. Another body B of mass 2 kg is dropped from a height of 50 m at the same time. Then :

One body is thrown up with velocity of 34.6ms 1. Another body is dropped from a height of 50m. Relative acceleration between the two bodies is

A body A is thrown vertically upwards with such a velocity that it reaches a maximum height of h. Simultaneously, another body B is dropped from height h. It strikes the ground and does not rebound. The velocity of A relative to B versus time graph is best represented by (upward direction is positive).

ALLEN-MOTION IN A PALNE-EXERCISE-1
  1. Which of the following statements is incorrect? (i) Average velocity i...

    Text Solution

    |

  2. Prove that the distances traversed during equal intervals of time by a...

    Text Solution

    |

  3. A body A is thrown up vertically from the ground with velocity V(0) an...

    Text Solution

    |

  4. A boy standing at the top of a tower of 20m of height drops a stone. A...

    Text Solution

    |

  5. A body is moving with velocity 30 m//s towards east. After 10 s its ve...

    Text Solution

    |

  6. A particle covers half of its total distance with speed v1 and the res...

    Text Solution

    |

  7. A particle starts from rest. Its acceleration at time t=0 is 5 m//s^(2...

    Text Solution

    |

  8. The motion of a particle along a straight line is described by equatio...

    Text Solution

    |

  9. A particle has initial velocity (2hati+3hatj) and acceleration (0.3hat...

    Text Solution

    |

  10. A stone is dropped from a height h . It hits the ground with a certain...

    Text Solution

    |

  11. A man runs at a speed of 4m//s to overtake a standing bus. When he is ...

    Text Solution

    |

  12. Let r(1)(t)=3t hat(i)+4t^(2)hat(j) and r(2)(t)=4t^(2) hat(i)+3that(j...

    Text Solution

    |

  13. A stone falls freely under gravity. It covered distances h1, h2 and h3...

    Text Solution

    |

  14. A ball whose kinetic energy is E , is projected at an angle of 45(@) t...

    Text Solution

    |

  15. A body is projected at such an angle that the horizontal range is thre...

    Text Solution

    |

  16. A body is thrown with some velocity from the ground. Maximum height wh...

    Text Solution

    |

  17. A body is thrown with a velocity of 9.8 m//s making an angle of 30^(@)...

    Text Solution

    |

  18. The maximum range of a gun on horizontal terrain is 1km. If g = 10 ms^...

    Text Solution

    |

  19. Two projectiles of same mass and with same velocity are thrown at an a...

    Text Solution

    |

  20. At the appermost point of a projectile its velocity and acceleration ...

    Text Solution

    |