Sir Isaac Newton deduced that the weight of an object is due to the force of gravity - Leaving Cert Physics - Question 6 - 2014

Newton's law of universal gravitation states that the force of attraction between two masses is proportional to the product of the masses and inversely proportional to the square of the distance between their centers. This can be mathematically expressed as:

$F \propto \frac{m_1 m_2}{r^2}$

where $m_1$ and $m_2$ are the two masses, and $r$ is the distance between their centers.

To find the acceleration due to gravity on Mars, we use:

$g = \frac{GM}{r^2}$ where:

• $G = 6.67 \times 10^{-11} \; \text{N m}^2/\text{kg}^2$,
• $M = 6.4 \times 10^{23} \; \text{kg}$, and
• $r = 3.4 \times 10^6 \; \text{m}$.

Substituting the values, we get:

$g = \frac{(6.67 \times 10^{-11}) (6.4 \times 10^{23})}{(3.4 \times 10^6)^2} \approx 3.7 \; \text{m/s}^2$

The wheels of the Curiosity rover are designed for the lower gravity on Mars. Since Mars has less gravitational force than Earth, the wheels would need to withstand different physical demands on Earth, which could lead to structural differences and make them less effective on solid surfaces.

To find the weight of Curiosity on Earth, we use the formula:

$W = mg$ where:

• $m = 899 \; \text{kg}$,
• $g = 9.8 \; \text{m/s}^2$.

Thus,

$W = 899 \times 9.8 \approx 8803 \; \text{N}$

The mass of an object remains constant regardless of location. Therefore, the mass of Curiosity on Mars is still:

$m = 899 \; \text{kg}$

To find the weight of Curiosity on Mars, we again use the weight formula:

$W = mg$ where now:

• $g = 3.7 \; \text{m/s}^2$.

Thus,

$W = 899 \times 3.7 \approx 3326.3 \; \text{N}$

One other part of the electromagnetic spectrum is ultraviolet radiation.