A body falling under the action of gravity has?

Question

A: maximum height

B: maximum weight

C: no weight

D: variable weight

Please help me with this question. Answer only if you know it and please explain your answer. I'll be very thankful to you...

Answer 1

c

you are in free fall and have no weight.

"But i am a bit confused. Every body has some weight"

That's just not true. Your weight is there only because you are in earth's gravitational field and you are resisting it.  On the moon, you would weigh about 1/6th of what you do now. When you ride a down elevator, your weight decreases for a bit. When you ride an up elevator, your weight increases a bit.

Don't get weight confused with mass. You have mass, that doesn't change, unless you go on a diet. mass is constant, in space, on the moon, in an elevator, your mass will not change.

In common language, mass and weight are often confused and interchanged. Physics (and other sciences) makes a careful distinction between them.

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Answer 2

Let us consider the actual weight of the object. Weight of an object is the force with which Earth pulls it.

Weight = mass * g, where g is acceleration due to gravity.

Mass remains same.

For small height g remains almost the same.

If you neglect small change in g, then weight is constant. Therefore, none of given options is correct.

But if the object is falling from such a huge height that change in g cannot be neglected, then g changes. Therefore D is correct.

But now suppose that instead of actual weight, we consider the weight measured by a spring balance, then the answer is C.

This is because spring balance measures tension in the spring.

Let m = mass of object

g = acceleration due to gravity

T = tension in spring

Then there are two forces on the object. One is weight mg downward.

Another is tension T upward.

Therefore, net downward force = mg - T

If a = acceleration of the object, then net downward force = ma

Therefore, mg - T = ma

The object is falling under gravity. Therefore, a = g

Therefore, mg - T = mg

Or, T = mg - mg = 0

Tension in the spring = 0

Therefore, the spring balance will measure weight as 0.

Note that the spring balance is falling together with the object.

So, the answer depends on what the questioner means. Is he talking of actual weight or measured weight? Is he willing to neglect variation in g with height or not?

Usually, for such questions, measured weight is meant. In that case the answer is C.

Answer 3

weight is the gravitational attraction between two objects it's really weird to think about but when you reach terminal velocity there is no attraction acting on you.

Answer 4

Weight (not mass) is the force of attraction of a body to another (larger) body.  Imagine yourself in an enclosed elevator.  Let that elevator fall under the influence of gravity.  It will accelerate at the rate of g (9.8 m/s^2).  If you have a ball in your hand and let it go, it also falls at the rate of g.  As a result, the ball stays right where you left it.  If you put it on a scale that is in the elevator, the scale reads zero, therefore, the ball has no weight, but it still has mass.

Interestingly, this thought experiment is like the one used by Einstein to demonstrate the equivalence of gravity and inertia and led to the General Theory of Relativity.

Answer 5

Maximum height exists only if you know where the body started falling from or it was launched upward and then fell back down.

Weight could be thought to be variable since the gravity becomes stronger the closer to the Earth it gets. Weight is a function of mass and gravity, so it could change even though mass stays the same. If weight is thought to be variable, then its maximum weight occurs at its lowest elevation.

The body has weight if it is in a gravitational field, so "no weight" doesn't work.

So id say A,B,D could be true and C is out.

Answer 6

The answer is C.

Think of the Space Shuttle in orbit.  It's falling under the action gravity and the astronauts are weightless.