Home
Class 11
PHYSICS
A lift is coming from 8th floor and is j...

A lift is coming from `8th` floor and is just about to reach `4th` floor. Taking ground floor as origin and positive direction upwards for all quantities, which one of the following is correct ?

A

x < 0, v < 0, a > 0

B

x > 0, v < 0, a < 0

C

x > 0, v < 0, a > 0

D

x > 0, v > 0, a > 0

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to analyze the motion of the lift as it travels from the 8th floor to the 4th floor, taking the ground floor as the origin (0 position) and considering the positive direction to be upwards. ### Step-by-Step Solution: 1. **Identify the Positions**: - Ground floor (0th floor) = 0 - 4th floor = 4 - 8th floor = 8 2. **Determine the Displacement (x)**: - Displacement is calculated as: \[ x = \text{final position} - \text{initial position} \] - Here, the lift is moving from the 8th floor (initial position) to the 4th floor (final position): \[ x = 4 - 8 = -4 \] - Therefore, the displacement \( x < 0 \). 3. **Determine the Velocity (v)**: - The velocity of the lift is in the direction of the displacement. Since the lift is moving downwards (from 8th to 4th floor), the velocity will also be negative: \[ v < 0 \] 4. **Determine the Acceleration (a)**: - As the lift approaches the 4th floor, it is about to stop. This means that the velocity of the lift is decreasing. Since the lift is moving downwards but slowing down, the acceleration must be in the opposite direction (upwards): \[ a > 0 \] 5. **Summarize the Results**: - Displacement \( x < 0 \) - Velocity \( v < 0 \) - Acceleration \( a > 0 \) 6. **Conclusion**: - Based on the analysis, the correct option is that displacement is negative, velocity is negative, and acceleration is positive.

To solve the problem, we need to analyze the motion of the lift as it travels from the 8th floor to the 4th floor, taking the ground floor as the origin (0 position) and considering the positive direction to be upwards. ### Step-by-Step Solution: 1. **Identify the Positions**: - Ground floor (0th floor) = 0 - 4th floor = 4 - 8th floor = 8 ...
Promotional Banner

Topper's Solved these Questions

  • MOTION IN A STRAIGHT LINE

    NCERT FINGERTIPS ENGLISH|Exercise ASSERTION AND REASON|15 Videos
  • MOTION IN A STRAIGHT LINE

    NCERT FINGERTIPS ENGLISH|Exercise Higher Order Thinking Skills|10 Videos
  • MOTION IN A STRAIGHT LINE

    NCERT FINGERTIPS ENGLISH|Exercise HOTS|10 Videos
  • MOTION IN A PLANE

    NCERT FINGERTIPS ENGLISH|Exercise Assertion And Reason|15 Videos
  • OSCILLATIONS

    NCERT FINGERTIPS ENGLISH|Exercise Assertion And Reason|15 Videos

Similar Questions

Explore conceptually related problems

A uniform plank is resting over a smooth horizontal floor and is pulled by applying a horizontal force at its one end. Which of the following statements are not correct?

A uniform plank is resting over a smooth horizontal floor and is pulled by applying a horizontal force at its one end. Which of the following statements are not correct?

A particle is resting over a smooth horizontal floor. At t = 0, a horizontal force starts acting on it. Magnitude of the force increases with time according to law F = alpha t, Where alpha is a positive constant. From figure, which of the following statements are correct ?

A wheel is released on a rough horizontal floor after imparting it an initial horizontal velocity v_(0) and angular velocity omega_(0) as shown in the figure below. Point O is the centre of mass of the wheel and point P is its instantaneous point of contact with the groundl. The radius of wheel is r and its radius of gyration about O is k . Coefficient of friction between wheel and ground is mu . A is a fixed point on the ground. Which of the following is conserved ?

Consider the Bohr's model of a one-electron atom where the electron moves around the nucleus. In the following, List-I contains some quantities for the n^("th") orbit of the atom and List-II contains options showing how they depend on n. Which of the following options has the correct combination considering List-I and List-II?

A 1.5 kg block placed on a frictless orizontal floor is pulled by a force F Direction of the force is unchanged and its magnitude is incrcresaed with time according to the equation F =0.5 t n where t denotes time in second . Which of the following is /are correct for subsequunt motion after t=0 s? [ g=10m//s^(2) ]

Five persons entered the lift cabin on the ground floor of a 8 floor house. Suppose each of them can leave the cabin independently at any floor beginning with the first. The total number of ways in which each of the five person can leave the cabin at any one of the 7 floor, is (a) 5^(7) (b) 7^(5) (c) 35 (d) 2520

A thin and uniform rod of mass M and length L is held vertical on a floor with large friction. The rod is released from rest so that it falls by rotating about its contact-point with the floor without slipping. Which of the following statement(s) is(are) correct, when the rod makes an angle 60° with vertical? [g is the acceleration due to gravity]

9 persons enter a lift from ground floor of a building which stops in 10 floors (excluding ground floor), if it is known that persons will leave the lift in groups of 2,3, & 4 in different floors. In how many ways this can happen?

A person in a lift is holding a water jar, which has a small hole at the lower end its side. When the lift is at rest, the water jet coming out of the hole hits the floor of the lift at a distance d of 1.2 m from the person. In the following, state of the lift’s motion is given in Column I and the distance where the water jet hits the floor of the lift is given in Column II. Match the statements from list I with those in list II and select the correct answer using the code given below the lists.