Suppose an apple weighs 0.9 N. What is its mass in kilograms? What is its weight in pounds?

Answer 1

I do not know where our learned sojsail came from but here on Earth the acceleration due to gravity g = 9.81m/s^2
(One should not feel bad about making mistakes. We are human after all... I hope)

So m=W/g= 0.9/9.81=0.0917kg

And he correctly stated that 1N=.22481 lbf

so we will have 0.9N=0.20233 lbf

Answer 2

Gosh, some people can't help being over-complex. The energy relationship between mass and velocity is simple. If I put a 1 Kg weight on your foot, it won't hurt. If I drop it from 2m, it will hurt somewhat. If I drop it from 200m it could crush your foot. So, obviously the energy in a body must consist of its mass and velocity. Then very simply, as you up the velocity, the energy goes up by the square - a top baseball pitcher only thows about 5 times faster than a child, but his ball will hit you with 25 times the force. E=mc^2 is simply an extension of the kinetic energy formula e=mv^2 that you learn in high school physics. The difference is that in the nuclear formula you are considering a total conversion of mass to energy, where the result is electro-magnetic radiation travelling at light speed. Recall that light-speed is really the wrong term, as light is simply a small fraction of the electromagetic spectrum, which includes radio waves all the way up to x-rays.

Answer 3

W = 0.9 N = m*g
where g = 0.8 m/s^2
You'll need to know that 1 N = 1 kg*m/s^2

1 N = 0.2248 lbs