Answer: approximately 0.7154 Newtons.
The weight of an object can vary depending on the gravitational force acting upon it. On the moon, the gravitational force is about 1/6th of the Earth's gravity. To find the weight of the lunar rock when brought back to Earth, we need to consider Earth's gravity.
To calculate the weight of an object, we use the formula:
Weight = mass × gravity
Given that the mass of the lunar rock is 73 grams, we need to convert it to kilograms by dividing it by 1000:
Mass in kilograms = 73 grams ÷ 1000 = 0.073 kg
Now we can calculate the weight of the lunar rock on Earth. Earth's gravity is approximately 9.8 m/s².
Weight on Earth = 0.073 kg × 9.8 m/s² = 0.7154 Newtons (N)