Question

which force requires contact?

a. the force of attraction between two masses

b. the force produced by interactions between magnetic objects

c. the force produced by interactions between electrically charged objects

d. the force exerted by air as an object moves through it

Explanation:

• Option A: Gravitational force (force of attraction between two masses) is a non - contact force. It acts at a distance based on the masses and the distance between them (Newton's law of gravitation \(F = G\frac{m_1m_2}{r^{2}}\)).
• Option B: Magnetic force (force produced by interactions between magnetic objects) is a non - contact force. Magnets can attract or repel each other without physical contact.
• Option C: Electrostatic force (force produced by interactions between electrically charged objects) is a non - contact force. Charged objects can exert forces on each other from a distance (Coulomb's law \(F=k\frac{q_1q_2}{r^{2}}\)).
• Option D: Air resistance (the force exerted by air as an object moves through it) is a contact force. The air molecules must come into contact with the object to exert a force on it.

Answer:

D. The force exerted by air as an object moves through it