Home
Class 12
PHYSICS
Consider the following statements, regar...

Consider the following statements, regarding a girl who wants to jump vertically upward from a hard horizontal floor. Symbolic representation of forces is given below. `vec(F)_(M)` = force developed in leg muscles, `vec(F)_(W)` = Weight, `vec(F)_(N)` = Normal reaction

A

Total force on floor is `vec(F)_(M)+vec(f)_(w)`.

B

Resultant force on girl is `(-vec(F)_(M))` while girl is in contact with floor.

C

Floor exerts a force `vec(F)_(N)` on girl.

D

The harder the girl pushes down, the greater the resulting acceleration of girl.

Text Solution

Verified by Experts

The correct Answer is:
C, D
When the girl is bending her legs, the total force exerted by her legs in the action, normal force by grand is the reaction. Considering FBD of girl
`vec(F)_(N)+vec(F)_(w)=mvec(a)`
`vec(F)_(N)=-vec(F)_(M)`
So force on floor is `vec(F)_(M)`
Resultant force on giel is `vec(F)_(w)-vec(F)_(M)`
Note: If we say the change in force of girl is `vec(F)_(M)`, then (A) and (B) would also be correct.
Promotional Banner

Topper's Solved these Questions

  • MASTER PRACTICE PROBLEM

    BANSAL|Exercise Subjective|107 Videos

  • MASTER PRACTICE PROBLEM

    BANSAL|Exercise Additional topic|70 Videos

  • MASTER PRACTICE PROBLEM

    BANSAL|Exercise Reasoning|75 Videos

  • FLUID MECHANICS

    BANSAL|Exercise PYQS AIEEE|10 Videos

  • SEMICONDUCTORS

    BANSAL|Exercise CBSE Question|32 Videos

Similar Questions

Explore conceptually related problems

A smooth track in the form of a quarter circle of radius 6 m lies in the vertical plane. A particle moves from P_(1) to P_(2) under the action of forces vec F_(1),vecF_(2) and vec F_(3) Force vec F_(1) is 20N, Force vec F_(2) is always 30 N in magnitude. Force vec F_(3) always acts tangentiallly to the track and is of magnitude 15 N . Select the correct alternative (s) : .

A smooth track is in the form of a quarter circle of radius 10 m lies in the vertical plane. A bead moves from A and B along the circular track under the action of forces vec(F)_(1),vec(F)_(2) and vec(F)_(3) Force vec(F)_(1) acts always towards point B and is always 20 N in magnitude Force vec(F)_(2) always acts horizontally and is always 25 N in magnitude. Force vec(F)_(3) always acts tangentially to the track and is of constant magnitude 10 N. Select the correct answer.

STATEMENT -1 : Net force on a particle w.r.t an inertial frame does notdepend on the velocity of the intertial frame. , STATEMENT - 2 : If net force on A is vec(F)_(A) and net force on B is vec(F)_(B) then force on A w.r.t B is (ven(F)_(A) - vec(F)_(B)) . STATEMENT - 2 : If acceleration of A is vec(a)_(A) and acceleration of B is vec(a)_(B) then, the acceleration of A w.r.t B is ( vec(a)_(A) - vec(a)_(B))

A wheel rolls purely between a rough horizontal surface below it and a horizontal plank above it under the action of a horizontal force F applied on the plank. If at any time vec(v)_(p) and vec(v)_(c) represent velocity of plank and velocity and vec(a)_(p) and vec(a)_(c) represent acceleration of plank and acceleration of centre of mass of wheel respectively then which of the following is // are correct.

A force acting on a certain particle depends of the particles position in the xy-plane. This force F is given by the expression vec(F) = (xy hat(i) + xy hat(j)) (1 N//m^(2)) where x and y are expressed in metre. If vec(F) is a conservation force ?

AB is a quarter of a smooth horizontal circular track of radius R,A particle P of mass m moves along the track from A to B under the action of following forces: vec(F_(1) =F (always towards y-axis) vec(F_(2)) =F (always towards point B) vec(F_(3)) =F (always along the tangent to path AB) vec(F_(4)) =F (always towards x-axis) {:(ColumnI," ",ColumnII),((A) "Work done by" vec(F_(1))," ",(P) sqrt(2)FR),((B) "Work done by" vec(F_(3))," ",(Q)FR),((C) "Work done by" vec(F_(3))," ",(R) (piFR)/(2)),((D) "Work done by" vec(F_(4))," ",(S) (2FR)/(pi)):} Select correct alternative :-

The linear momentum of a particle is given by vec(P)=(a sin t hati- acos t hatj) kg- m//s . A force vec(F) is acting on the particle. Select correct alternative/s:

A moving particle of mass m is acted upon by five forces vec(F)_(1),vec(F)_(2),vec_(F)_(3),vec(F)_(4) and vec(F)_(5 . Forces vec(F)_(2) and vec(F)_(3) are conservative and their potential energy functions are U and W respectively. Speed of the particle changes from V_(a) to V_b when it moves from position a to b. Which of the following statement is/are true – (a) Sum of work done by vec(F)_(1),vec(F)_(4) and vec(F)_(5)=U_(b)-U_(a)+W_(b)-W_(a) (b) Sum of work done by vec(F)_(1),vec(F)_(4) and vec(F)_(5)=U_(b)-U_(a)+W_(b)-W_(a)+1/2m(V_(a)^(2)-V_(a)^(2)) (c) Sum of work done by all five forces =1/2m(V_(b)^(2)-V_(a)^(2)) (d) Sum of work done by vec(F)_(2) and vec(F)_(3)=(U_(b)+W_(b))-(U_(a)+W_(a))

BANSAL-MASTER PRACTICE PROBLEM-Multiple objective
  1. Figure shows a man pulling on a string attached to a block kept on a r...

    Text Solution

    |

  2. A box is accelerating with acceleration =20m//s^(2). A block of mas 10...

    Text Solution

    |

  3. Consider the following statements, regarding a girl who wants to jump ...

    Text Solution

    |

  4. A 10 kg block is at rest as shown on a horizontal surface having a coe...

    Text Solution

    |

  5. Monkey (1) is climbing up a light rope with acceleration of a(1)=2m//s...

    Text Solution

    |

  6. A particle of mass m is going along surface of smooth hemisphere of ra...

    Text Solution

    |

  7. Block m(1) is projected on a long plank of mass m(2) plank is placed o...

    Text Solution

    |

  8. An object of mass m is slowly pushed some partway up a verticle up a v...

    Text Solution

    |

  9. A block of mass 1 kg kept on a rough horizontal surface (mu=0.4) is at...

    Text Solution

    |

  10. Consider the situation in which smooth ball of mass M is hanging in eq...

    Text Solution

    |

  11. Two identicle blocks A and B are placed on two inclined planes as show...

    Text Solution

    |

  12. A particle initially at rest on a smooth horizontal surface, is acted ...

    Text Solution

    |

  13. A particle of mass m suspended by a string of length l revolves in a h...

    Text Solution

    |

  14. For a curved track of radius R, banked at angle theta

    Text Solution

    |

  15. On a train moving along east with a constant speed v, a boy revolves a...

    Text Solution

    |

  16. A heavy particle is attached to one end of a string 1m long whose othe...

    Text Solution

    |

  17. A chain of length L and mass per unit length rho is piled on a horizon...

    Text Solution

    |

  18. Two students were given a physics problem for finding maximum extensio...

    Text Solution

    |

  19. Consider a cart of mass M on a frictionless surface that can hold a fu...

    Text Solution

    |

  20. Two blocks A and B of the same mass are connected to a light spring an...

    Text Solution

    |