Q11. A person has a mass of 70 kg. What is this person's weight? What is the force that this person exerts onto the Earth? What is the Earth's acceleration because of this person?
To find the person's weight, we can use the formula: weight = mass x gravity.
1. Weight: The person's weight can be calculated by multiplying their mass with the acceleration due to gravity. On Earth, the average acceleration due to gravity is approximately 9.8 m/s^2.
Weight = mass x acceleration due to gravity
Weight = 70 kg x 9.8 m/s^2
2. Force exerted on Earth: According to Newton's third law of motion, for every action, there is an equal and opposite reaction. So, the force with which the person exerts onto the Earth is equal to the force with which the Earth exerts onto the person. Therefore, the person's weight is equal to the force exerted on the Earth.
Force exerted on the Earth = Weight
Force exerted on the Earth = 70 kg x 9.8 m/s^2
3. Earth's acceleration due to the person: The Earth experiences an acceleration due to the person's presence, but since the mass of the Earth is extremely large compared to the person, the resulting acceleration is negligible. Therefore, we can consider the Earth's acceleration due to this person as zero or negligible.
In summary:
- Weight = 70 kg x 9.8 m/s^2
- Force exerted on Earth = 70 kg x 9.8 m/s^2
- Earth's acceleration due to the person ≈ 0 or negligible.
70*9.81 = ___ N
same force on the earth.
Now, F=ma so divide by earth's mass.