Choose all the answers that apply. which of the following forces require physical contact?
a. tension
b. air resistance
c. friction
d. magnetic force
e. applied force

choose all that apply !

The answers are:

A. Tension

B. Air resistance

C. Friction

E. Applied force

Let's discard each given option in order to find what forces requires physical contact:

A. Tension, correct: Tension force appears when it's a force pulling another object, trying to move it in the same direction, the tension usually involves a rope or cable used to pull another object. For example, a mass being held with a rope/cable.

B. Air resistance, correct: Air resistance, or drag, is a force acting in the opposite direction of a body in motion when it's passing through the air, involving contact between the air molecules and the surface of the object. For example, when an airplane is flying, it's being affected by the air resistance, making it move slower.

C. Friction, correct: The friction appears when there is an object surface being in contact with another object surface, both or just one can be in motion, the frictional forces always go in the opposite direction of the motion. For example, when you try to pull a box from a place to another, there is always a force that opposes to the movement, making you to apply more force in order to move the object,  it's the frictional force.

D. Magnetic force, incorrect: Magnetic force does not require physical contact between objects. The magnetic force acts on an object, pulling or attracting it. For example, using a magnet to attract a metallic object does not involve any physical contact, the force acts on the metallic object attracting it with no contact.

E. Applied force, correct: The applied forces involve physical contacts, applying forces on an object can result in the object motion. For example, pushing a button, the button us bein affected by an applied force and it will move in the same direction that the force.

Have a nice day!

two charges are fixed in place on the x-axis as shown. the charge at x = 0 is negative and has magnitude q = 2 μcoulombs (1 μcoulomb = 10-6 coulombs). the charge at x = d, (d = +12 cm), is positive and has magnitude q = 4 μcoulombs. find a point x = xo along the x-axis at which the electric field is zero.

it is b. absorbs thermal energy