The contact force is indeed caused by "Contact".
Air resistance is basically a type of friction, which is apparently present providing two object contact.
The rest selections are all interaction force, which is not necessarily caused by contact.
It is the same if a white father and a white mother give birth to a black kid, so the mother accuses the father for having (let's say mating) with a black women.
Answer: What is this supposed to be converted into?
Explanation:
Answer: 
Explanation:
According to Newton's 2nd Law of motion the force 
is proportional to the mass 
and acceleration 
:
(1)
On the other hand, the equation for the Centripetal force is:
(2)
Where:
is the velocity
is the radius of the circular motion
Making (1) and (2) equal:
(3)
Hence:
This is the expression for the centripetal acceleration
It should be noted, this acceleration is directed toward the center of the circumference of the circular motion (that's why it's called centripetal acceleration).
Answer:
1.8 cm
Explanation:
= mass of the singly charged positive ion = 3.46 x 10⁻²⁶ kg
= charge on the singly charged positive ion = 1.6 x 10⁻¹⁹ C
=Potential difference through which the ion is accelerated = 215 V
= Speed of the ion
Using conservation of energy
Kinetic energy gained by ion = Electric potential energy lost
= Radius of the path followed by ion
= Magnitude of magnetic field = 0.522 T
the magnetic force on the ion provides the necessary centripetal force, hence
