Home
Class 12
PHYSICS
An elevator is accelerating upward at a ...

An elevator is accelerating upward at a rate of `6ft(sec^(2)` when a bolt from its celling falls to the floor of the lift (Distance=9.5feet). The time taken (in seconds) by the falling bolt to hit the floor is (take `g=32ft//sec^(2)`)

A

`sqrt(2)`

B

`(1)/sqrt(2)`

C

`2sqrt(2)`

D

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

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to determine the time taken by a bolt to fall from the ceiling of an accelerating elevator to the floor of the elevator. Here’s the step-by-step solution: ### Step 1: Understand the scenario The elevator is accelerating upward at a rate of \(6 \, \text{ft/s}^2\). The bolt falls from the ceiling of the elevator to the floor, which is \(9.5 \, \text{feet}\) apart. The acceleration due to gravity \(g\) is given as \(32 \, \text{ft/s}^2\). ### Step 2: Determine the effective acceleration of the bolt Since the elevator is accelerating upward, the effective acceleration acting on the bolt (with respect to the elevator) will be the sum of the gravitational acceleration and the elevator's acceleration. Therefore, the effective acceleration \(a\) of the bolt is: \[ a = g + \text{(acceleration of the elevator)} = 32 \, \text{ft/s}^2 + 6 \, \text{ft/s}^2 = 38 \, \text{ft/s}^2 \] ### Step 3: Use the kinematic equation We can use the kinematic equation for motion under constant acceleration to find the time \(t\) taken for the bolt to fall: \[ s = ut + \frac{1}{2} a t^2 \] Where: - \(s\) is the distance fallen (which is \(9.5 \, \text{feet}\)), - \(u\) is the initial velocity (which is \(0 \, \text{ft/s}\) since the bolt starts from rest), - \(a\) is the effective acceleration (\(38 \, \text{ft/s}^2\)), - \(t\) is the time in seconds. Substituting the known values into the equation: \[ 9.5 = 0 + \frac{1}{2} \cdot 38 \cdot t^2 \] This simplifies to: \[ 9.5 = 19 t^2 \] ### Step 4: Solve for \(t^2\) Rearranging the equation gives: \[ t^2 = \frac{9.5}{19} \] Calculating \(t^2\): \[ t^2 = 0.5 \] ### Step 5: Calculate \(t\) Taking the square root of both sides to find \(t\): \[ t = \sqrt{0.5} = \frac{1}{\sqrt{2}} \, \text{seconds} \] ### Final Answer The time taken by the falling bolt to hit the floor of the elevator is: \[ t = \frac{1}{\sqrt{2}} \, \text{seconds} \approx 0.707 \, \text{seconds} \] ---

To solve the problem, we need to determine the time taken by a bolt to fall from the ceiling of an accelerating elevator to the floor of the elevator. Here’s the step-by-step solution: ### Step 1: Understand the scenario The elevator is accelerating upward at a rate of \(6 \, \text{ft/s}^2\). The bolt falls from the ceiling of the elevator to the floor, which is \(9.5 \, \text{feet}\) apart. The acceleration due to gravity \(g\) is given as \(32 \, \text{ft/s}^2\). ### Step 2: Determine the effective acceleration of the bolt Since the elevator is accelerating upward, the effective acceleration acting on the bolt (with respect to the elevator) will be the sum of the gravitational acceleration and the elevator's acceleration. Therefore, the effective acceleration \(a\) of the bolt is: \[ ...
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 lift starts ascending with an acceleration of 4 ft//s^(2) . At the same time a bolt falls from its cieling 6ft above the floor. Find the time taken by it to reach the floor. g= 32 ft//s^(2)

A lift, initially at rest on the ground, starts ascending with constant acceleration 8m//s^(2) After 0.5 seconds, a bolt falls off the floor of the lift. The velocity of the lift at the instant the bolt hits the ground is m/s .[Take g=10 m//s^(2) ]

Starting from rest, A lift moves up with an acceleration of 2 ms^(-2) . In this lift , a ball is dropped from a height of 1.5m (with respect to floor of lift). The time taken by the ball to reach the floor of the lift is ( g=10 ms^(-2) )

A lift is moving with a uniform downward acceleration of 2 m//s^(2) . A ball is dropped from a height 2 m from the floor of lift. Find the time taken after which ball will strke the floor ? (Take g = 10 m//s^(2) )

A young man of mass 60 kg stands on the floor of a lift which is acceleration downwards at 1m//s^(2) then the reaction of the floor of the lift on the man is (Take g = 9.8 m//s^(2) )

A very broad elevator is going up vertically with a constant acceleration of 2m//s^(2) . At the instant when its velocity is 4m//s , a ball is projected from the floor of the lift wht as of 4m//s relative to the floor at an elevation of 30^(@) . The time taken by the ball to return the floor is (g=10m//s^(2))

A ball is thrown vertically upwards from a height of 40 m and hits the ground with a speed that is three times its initial seepd. What is the time taken (in sec) for the fall ?

An elevator (lift) ascends with an upward acceleration of 1.2ms^-2 . At the instant when its upward speed is 2.4 ms^-1 , a loose bolt drops from the ceiling of the elevator 2.7m above the floor of the elevator. Calculate (a) the time of flight of the bolt from the ceiling to the floor and (b) the distance it has fallen relaative to the elevator shaft.

An elevator (lift) ascends with an upward acceleration of 1.2 ms^(-2) .At the instant when its upward speed is 2.4 ms^(-1) , a loose bolt drops from the ceiling of the elevator 2.7 m above the floor of the elevator . Calculate (a) the time of flight of the bolt from the ceiling to the floor and (b)the distance it has fallen relative to the elevator shaft.

ALLEN-MOTION IN A PALNE-EXERCISE-1
  1. A river 4.0 miles wide is following at the rate of 2 miles/hr. The min...

    Text Solution

    |

  2. A point traversed half the distance with a velocity v(0). The remainin...

    Text Solution

    |

  3. An elevator is accelerating upward at a rate of 6ft(sec^(2) when a bol...

    Text Solution

    |

  4. A stone is thrown vertically upwards. When stone is at a height half o...

    Text Solution

    |

  5. Velocity-time graph for a moving object is shown in the figure. Total ...

    Text Solution

    |

  6. When a ball is thrown up vertically with velocity v0, it reaches a max...

    Text Solution

    |

  7. A car acquires a velocity of 72 km//h in 10 seconds starting from rest...

    Text Solution

    |

  8. An iron ball and a wooden ball of the same radius are released from a ...

    Text Solution

    |

  9. A particle moves along a straight line OX. At a time t (in seconds) th...

    Text Solution

    |

  10. Two bodies A (of mass 1 kg) and B (of mass 3 kg) are dropped from heig...

    Text Solution

    |

  11. A river 2 km wide is flowing at the rate of 2km/hr. A boatman, can row...

    Text Solution

    |

  12. A particle moving along x-axis has acceleration f, at time t, given by...

    Text Solution

    |

  13. The position x of a particle with respect to time t along the x-axis i...

    Text Solution

    |

  14. Two cars A and B start moving from the same point with same velocity v...

    Text Solution

    |

  15. An object travels 10km at a speed of 100 m/s and another 10km at 50 k/...

    Text Solution

    |

  16. Which of the following relations representing displacement x (t) of pa...

    Text Solution

    |

  17. The distance travelled by a particle starting from rest and moving wit...

    Text Solution

    |

  18. A particle moves in a straight line with a constant acceleration. It c...

    Text Solution

    |

  19. A particle shows distance-time curve as given in this figure. The maxi...

    Text Solution

    |

  20. The velocity-time graph of an objects is as shown. The displacement du...

    Text Solution

    |