Free Fall or What? Weight Change Explained

In summary, the conversation discusses the concept of apparent weight in an elevator and how it changes during acceleration and deceleration. The speakers also mention the role of inertia and Newton's third law in this phenomenon.
  • #1
cterence_chow
20
0
free fall or what??!?

I would like to know,
if we are on a lift going upwards, and we happen to be standing on a weighing machine, why does our the value appears more than when we just weigh in the stationary lift??
 
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  • #2
That's just the inertia of your body causing it to stay put for as long as possible. Both it, and the top of the scale itself, thus apply pressure to the bottom of the scale. Note that this occurs only during the acceleration phase of the elevator travel. By the same token, when it decelerates for the next stop, your apparent weight will drop.
 
  • #3
Then what if the lift is just accelerating downwards??Won't our apparent weight will also be less?
 
  • #4
For sure. As long as there's a positive acceleration, your weight will increase. With negative acceleration, it will decrease. Once a constant speed is reached in either direction, your weight will be normal (excluding relativistic effects which don't apply at that speed or within your own reference frame).
 
  • #5
E=mgh Potential Energy
 
  • #6
Clarification: the change in weight only occurs during the acceleration. The wording in the OP implies it occurs all the time when going up.
 
  • #7
F = ma.. in equilibrium,our body's weight is forcing downward. and there is a reaction force(same value and upward)= Newton's third law.when the lift is moving upward, the force acting upward increases. and that force also has a reaction force acting downward. this reaction force will be add to our weight value...
 

1. What is free fall?

Free fall is the motion of an object falling under the sole influence of gravity. This means that there are no other forces acting on the object to change its motion.

2. How does free fall affect weight?

In free fall, an object's weight does not change. However, its apparent weight can change depending on the acceleration due to gravity. If an object is in free fall, its apparent weight will be zero since it is accelerating downwards at the same rate as gravity.

3. Why do objects appear weightless in free fall?

Objects appear weightless in free fall because they are accelerating downwards at the same rate as gravity. This means that the force of gravity is cancelled out by the acceleration, resulting in a net force of zero and making the object feel weightless.

4. How is free fall different from other forms of motion?

Free fall is different from other forms of motion because it is the only form of motion where the net force acting on an object is equal to zero. In other forms of motion, there are usually other forces acting on the object that can change its motion.

5. What is the importance of understanding free fall in science?

Understanding free fall is important in science because it allows us to accurately predict the motion of objects under the influence of gravity. It also helps us understand the concept of weight and how it is affected by different factors, such as acceleration due to gravity.

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