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A man squatting on the ground gets strai...

A man squatting on the ground gets straight up and stand. The force of reaction of ground on the man during the process is.

A

constant and equal to mg in magnitude

B

constant and greater than mg in magnitude.

C

variable but always greater then mg

D

at first greater than mg and later becomes equal to mg

Text Solution

Verified by Experts

The correct Answer is:
D
In squatting, he is tilted some what, hence also has to balance frictional force besides his weight in this case R= friction + mg `implies Rgtmg`
When he set straight in that case,
R=mg
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Knowledge Check

  • A man is running on the ground .It is known that the coefficient of friction between the man and the ground is mu . Then which of the following statements is correct

    A
    Normal reaction between man and ground is equal to weight of man
    B
    The direction of friction on man is in the direction of normal reaction on the man
    C
    Direction of friction on man is opposite to the direction of motion of man
    D
    Maximum acceleration of man can be `2mug`

  • A boy of mass 50 kg standing on ground exerts a force of 500 N on the ground. The force exerted by the ground on the boy will be :

    A
    100 N
    B
    200 N
    C
    50000 N
    D
    500 N

  • A man of mass 80kg pushes box of mass 20kg horizontaly. The man moves the box with a constant acceleration of 2 m//s^(2) but his foot does not slip on the ground. There is no friction between the box and the ground. There is no friction between the box and the ground. whereas there is sufficient friction between the man's foot and the ground to prevent him from slipping. Assertion:- The force applied by the man on the box is equal and opposite to the force applied by the force applid by the box on the man. Reason:- Friction force applied by the ground on the man is 200N.

    A
    If both Assertion `&` Reason are True `&` the Reason is a correct explanation of the Assertion.
    B
    If both Assertion `&` Reason are True but Reason is not a correct explanation of the Assertion.
    C
    If Assertion is True but the Reason is False.
    D
    If both Assertion `&` Reason are False.

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