Question

a feather is droped on the moon from a height of 1.40 meters. acceleration of gravity on moon is 1.67m/s2. why we have take acceleration as -1.67

Answer 1

no you would take positive value here 1.67 because the direction of motion is same as direction of acceleration

Answer 2

you dropped it upward or downward.

Answer 3

If u select the direction of the motion of the feather in -ve direction then acceleration can be taken as -1.67. The point to be noted is that both acceleration and motion will be either +ve or -ve since they are in the same direction.

Answer 4

@Abhisar ,but when you get veclocity
V^2=2ax w
will give you positive value in the opposite direction of the motion which doesn't make sense(or you have to take negative rout value)

Answer 5

Suppose we take the downward direction as -ve, then a and w both will negative.

Answer 6

no i wrote w by wrong i mean \[V _{T}^{2} = 2 a x \]
then the direction of velocity will be in the opposite direction of x and a which doesn't make sense unless you take the negative value of v and that is amazing i have never done that before to take negative value 0_0