menu 3 Newton's Law of Gravitation Erasmus+: Key action 2:Strategic Partnerships in School Education # Practical exercise 4:

Calculate the weight of a person with mass 80 kg who is standing on different bodies in the Solar system.

## Aim:

To demonstrate the difference between mass and weight. To show how a person’s weight changes (and the mass does not) depending on the gravitational acceleration of the other body (which in turn depends on its mass and radius).

## Instructions for the teacher:

In the table below are listed some bodies from the Solar system with their masses, radii, and gravitational accelerations. The students have to calculate the gravitational force that the person experiences on each of the bodies, which in fact is the person’s weight on that body. The exercises shows the difference between mass and weight. While the person’s mass is always the same, the weight changes depending on the celestial body and the gravitational force. But in space, where the gravitational force is much weaker, the bodies can be almost weightless, i.e. the weight is very small.

Table:

 Name Mass(kg) Radius(km) Gravitational acceleration(m/s2 ) Weight of the person(kg) Moon 7.342×1022 1 737 1,62 Mercury 3.301×1023 2 440 3,7 Venus 4.8675×1024 6 052 8,87 Mars 6.4171×1023 3 390 3,72 Jupiter 1.8982×1027 69 911 24,79 Saturn 5.6834×1026 58 232 10,44 Uranus 8.6810×1025 25 362 8,87 Neptune 1.024 × 1026 24 622 11,15