<span>One everyday life experience that seems to support the geocentric model is the rising and setting of the Sun and Moon. The Moon rises and falls because it does revolve around the Earth and so it is easy to assume the same is true for the Sun.</span>
Answer:
a=4,32m/s^2
Explanation:
Fnet = F1 - F2
= 12-1.2
= 10.8N
m=2.5kg
Fnet =ma
10.8=2.5a then divide both sides by 2.5 to get acceleration
Answer
Nature of the surfaces.
Explanation
Friction is the the force that opposes motion between two surfaces that are in relative motion. If two objects are in contact, one of it or both must be in motion for friction to exist.
Friction is affected by a number of factors.
One is the weight of the object. The more the weight of the object the higher the friction between it and the surface.
The other factor is the nature of the surfaces. Rough surfaces contribute to high friction while smooth surfaces reduces the friction between surfaces.
The crate moves at constant velocity, this means that its acceleration is zero, so the net force acting on the crate is zero (Newton's second law).
There are only two forces acting on the crate: the force F applied by the worker and the frictional force, acting in the opposite direction:

, where

is the coefficient of friction and

is the mass of the crate. Since the net force should be equal to zero, the two forces must have same magnitude, so we have:

And so, this is the force that the worker must apply to the crate.