Question

A packet of weight W was allowed to fall freely in a water tank with acceleration'a' the magnitude of resistance force offered by water is

Answer 1

let the weight of packet is m.

and the two force mg and ma are working acting on this packet

so the force is resultant of alp forces..

w(1+a/g)

Answer 2

Given that,

Weight of packet = W

Acceleration = a

We know that,

Resistance force is $F_{d}$

When a packet fall freely in a water then the force mg will applied downward and resistance force will applied upward.

We need to calculate the magnitude of resistance force offered by water

Using balance equation

$W-F_{d}=ma$

Where, W = weight of packet

$F_{d}$ = resistance force

m = mass of packet

a = acceleration

Put the value of mass

$W-F_{d}=\dfrac{W}{g}a$

$F_{d}=W-\dfrac{W}{g}a$

$F_{d}=W(1-\dfrac{a}{g})$

Hence, the magnitude of resistance force offered by water is $W(1-\dfrac{a}{g})$

(c) is correct option.