Please help with this gravity problem

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So it is towards the moon. In summary, the apparent weight of a 78-kg astronaut 5200 km from the center of the Earth's Moon in a space vehicle moving at constant velocity is unknown. The magnitude of the apparent weight of a 78 kg astronaut 5200 km from the center of the Earth's Moon in a space vehicle accelerating toward the moon at 3.2 m/s^2 can be calculated using Newton's second law and the law of gravitational force. The weight will be in the direction towards the moon.
  • #1
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I really have no idea where to start or how to even do this...

(a) What is the apparent weight of a 78-kg astronaut 5200 km from the center of the Earth's Moon in a space vehicle moving at constant velocity?
(b) is this towards or away from the moon?
(c) What is the magnitude of the apparent weight of a 78 kg astronaut 5200 km from the center of the Earth's Moon in a space vehicle accelerating toward the moon at 3.2 m/s^2?
(d) is this towards or away from the moon?
 
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  • #2
Welcome to PF!

jfahlgr1 said:
(a) What is the apparent weight of a 78-kg astronaut 5200 km from the center of the Earth's Moon in a space vehicle moving at constant velocity?
(b) is this towards or away from the moon?
(c) What is the magnitude of the apparent weight of a 78 kg astronaut 5200 km from the center of the Earth's Moon in a space vehicle accelerating toward the moon at 3.2 m/s^2?
(d) is this towards or away from the moon?

Hi jfahlgr1! Welcome to PF! :smile:

I don't really understand question (a) … is that the whole question? :confused:

Let's go straight to question (c) …

the apparent weight is the force exerted by the astronaut's feet and the spaceship on each other …

calculate it using Newton's second law of motion, and the law of gravitational force. :smile:
 
  • #3
First of all you have to know the mass of the Moon first before getting the weight of the astronaut. You use this formula to find Fg:

Fg = [tex]\frac{GM}{r^2}[/tex]

where:
G = gravitational constant (6.67 * 10-11)
M = Mass of the Moon
r = 5,200,000 meters (5200 km)

After you get Fg then you mutiply it from the mass of the astronaut to get its weight.

The direction in question D is is towards the moon because you already said that the vehicle is accelerating towards the moon at 3.2 m/s2.
 

What is the formula for calculating gravity?

The formula for calculating gravity is F = G(m1m2)/r^2, where F is the force of gravity, G is the gravitational constant, m1 and m2 are the masses of the two objects, and r is the distance between the two objects.

How does mass affect gravity?

Mass directly affects gravity. The greater the mass of an object, the stronger its gravitational pull will be. This is why larger objects, like planets, have stronger gravitational forces than smaller objects, like rocks.

What is the difference between mass and weight?

Mass is a measure of the amount of matter an object contains, while weight is a measure of the force of gravity acting on an object. Mass is constant, but weight can vary depending on the strength of the gravitational pull.

How does distance affect gravity?

Distance also directly affects gravity. The farther apart two objects are, the weaker their gravitational pull will be. This is why the force of gravity between the Earth and the Moon is weaker than the force of gravity between the Earth and the Sun.

What are some real-life applications of the concept of gravity?

The concept of gravity is used in many aspects of life, including space travel, planetary motion, and even everyday activities like walking and throwing objects. Understanding gravity is crucial in fields like physics and engineering.

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