Answer:

Explanation:
Close to Earth's surface, the force of gravity that pulls an object towards the ground is
(2)
where
m is the mass of the object
g is the acceleration due to gravity, which is
close to Earth's surface
This is an approximation of the general formula of gravity valid only close to Earth's surface. The more general formula is
(1)
where
G is the gravitational constant
M is the Earth's mass
m is the object's mass
r is the distance of the object from Earth's center
At the Earth's surface,
r = R (Earth's radius), and by calling the following factor

we see that eq.(1) becomes eq.(2).
Given:
Lens.........diameter ...fl#
eyepiece...2cm............5
objective...40cm........15
focal length of eyepiece = 2*5 = 10cm
focal length of objective = 40*15 = 600cm
magnification = FL obj / FL eyp = 600/10 = 60x
The mass of a rollercoaster car moving at a velocity of 30 meters/second and has a momentum of 2.5 × 104 kilogram meters/second is 8.3 × 10²kg.
<h3>How to calculate mass?</h3>
The mass of the roller coaster car can be calculated using the following formula:
P = m × v
Where;
- P = momentum
- m = mass
- v = velocity
m = 2.5 × 10⁴ ÷ 30
m = 8.3 × 10²kg
Therefore, the mass of a rollercoaster car moving at a velocity of 30 meters/second and has a momentum of 2.5 × 104 kilogram meters/second is 8.3 × 10²kg.
Learn more about mass at: brainly.com/question/19694949
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I think atoms and molecules in matter are always in motion because of kinetic energy.
Answer:
Oxygen or more precisely, the O-15 isotope.