Question about acceleration and gravity

In summary: However, if they were in free fall (i.e. no contact with the platform) they would feel weightless as there would be no force acting on them.
  • #1
raeshun
11
0
I am having trouble understanding g-force.So if a object with a mass of 100 kg is sitting on a platform in space.If the platform was accelerating at 10 m/s^2 upwards would the weight of the object be 1000 kg? If so why?
 
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  • #2
The force on the platform would be

F=ma
=100kg x 10m/s2
=1000 Newtons (not Kg)

On Earth the force on the ground would be

F=mg
=100kg x 9.8m/s2
=980 Newtons.

About the same. So if this 100kg mass on the platform was a man he would feel roughly the same as he does on Earth (eg 1g).

To be precise he would be experiencing 10/9.8 = 1.02g
 
  • #3
raeshun said:
I am having trouble understanding g-force.So if a object with a mass of 100 kg is sitting on a platform in space.If the platform was accelerating at 10 m/s^2 upwards would the weight of the object be 1000 kg? If so why?
The kg is a measure of mass, not force. Weight is a force. So a "weight of 100kg" is scientifically incorrect. It is used in everyday speech to stand for "the force exerted by gravity at the Earth's surface on a 100kg mass", but in scientific terms that's (approximately) 1000 Newtons. Likewise, the force required to accelerate a 100kg mass at 10m/s2 in a weightless environment is 1000 N.
 
  • #4
CWatters said:
The force on the platform would be

F=ma
=100kg x 10m/s2
=1000 Newtons (not Kg)

On Earth the force on the ground would be

F=mg
=100kg x 9.8m/s2
=980 Newtons.

About the same. So if this 100kg mass on the platform was a man he would feel roughly the same as he does on Earth (eg 1g).

To be precise he would be experiencing 10/9.8 = 1.02g

haruspex said:
The kg is a measure of mass, not force. Weight is a force. So a "weight of 100kg" is scientifically incorrect. It is used in everyday speech to stand for "the force exerted by gravity at the Earth's surface on a 100kg mass", but in scientific terms that's (approximately) 1000 Newtons. Likewise, the force required to accelerate a 100kg mass at 10m/s2 in a weightless environment is 1000 N.

So if this happened on Earth ignoring air resistance would the person on the platform feel weightless?
 
  • #5
What might be confusing is that weighing scales measure the force an object puts on them so they should really be marked in Newtons not Kg. However since we don't normally take weighing scales to the moon they are calibrated for g=9.8 and marked in kg.

If you took kitchen weighing scales to the moon with a 1kg test mass you would discover they would read INCORRECTLY. For example they would under read by a factor of six yet the mass has not changed.
 
  • #6
raeshun said:
So if this happened on Earth ignoring air resistance would the person on the platform feel weightless?

EDIT: haruspex is correct below. If the platform was on Earth and accelerating upwards at 10m/s2 then would feel about 2g.
 
Last edited:
  • #7
raeshun said:
So if this happened on Earth ignoring air resistance would the person on the platform feel weightless?
If by "this" you mean the platform accelerating upwards at 10m/s2, they would feel a force of about 2g: 1g to stay put plus another to accelerate upwards.
 

What is the difference between acceleration and gravity?

Acceleration is the rate at which an object changes its velocity, while gravity is the force that pulls objects towards each other. Acceleration can be caused by various factors such as a change in speed or direction, while gravity is a constant force exerted by massive objects.

How do acceleration and gravity affect each other?

Acceleration and gravity are related in that the acceleration of an object in free fall due to gravity is always 9.8 meters per second squared (m/s²) near the Earth's surface. This means that objects will accelerate towards the Earth at a constant rate due to the force of gravity.

How does acceleration due to gravity differ on other planets?

The acceleration due to gravity on other planets is different from Earth due to variations in mass and size. For example, on the surface of the moon, the acceleration due to gravity is 1.6 m/s², while on Jupiter it is 24.8 m/s².

How can acceleration and gravity be measured?

Acceleration can be measured using a device called an accelerometer, which measures the change in velocity of an object. Gravity can be measured using a device called a gravimeter, which measures the strength of the gravitational field at a specific location.

What is the relationship between acceleration, velocity, and time?

The relationship between acceleration, velocity, and time can be described using the equation a = ∆v/∆t, where a is acceleration, ∆v is the change in velocity, and ∆t is the change in time. This means that the greater the acceleration, the larger the change in velocity over a given period of time.

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