Answer:
D. a person pulling a sled.
Explanation:
contact force only occurs when something directly comes in contact with another object.
a. is wrong because that is called magnetic force.
b. gravitational force
c. is an electrical force
This theory was first proposed by Nicolaus Copernicus. Copernicus was a Polish astronomer. He first published the heliocentric system in his book: De revolutionibus <span>orbium </span>coelestium<span> , "On the revolutions of the heavenly bodies," which appeared in 1543.</span>
Do you have any answer options?
The most I can help is to tell you that a covalent bond is a type of bond that shares electrons between the bonded atoms.
Answer:

Explanation:
The magnetic field produced by a current-carrying wire is given by

where
is the vacuum permeability
I is the current
r is the distance from the wire
In this problem we have

r = 1.2 mm = 0.0012 m
So the magnetic field strength is

Answer:All planets move in elliptical orbits, with the sun at one focus. This is one of Kepler's laws. The elliptical shape of the orbit is a result of the inverse square force of gravity. The eccentricity of the ellipse is greatly exaggerated here.
so it is true
Explanation: