Question

which of the following is an accurate statement regarding friction? * 10 points
friction acts in the same direction as the movement of an object.
friction produces heat.
objects with less mass have more friction.
the harder surfaces press together, the less friction there will be.

which of the following is an example of magnetism? * 10 points
a compass needle moving
pushing a shopping cart
rubbing your hands together when you are cold
a large boulder falling from a cliff

Explanation:

First Question:

• Friction acts opposite to the direction of an object's movement. So, the statement "Friction acts in the same direction as the movement of an object" is wrong.
• Friction force \(F_f=\mu N\) (\(\mu\) is the coefficient of friction, \(N\) is the normal force). Mass \(m\) and normal force \(N\) (in horizontal - surface cases \(N = mg\)) are related, but less - mass objects don't have more friction. The statement "Objects with less mass have more friction" is wrong.
• The formula \(F_f=\mu N\), when surfaces press harder (\(N\) increases), \(F_f\) (friction) increases. So, the statement "The harder surfaces press together, the less friction there will be" is wrong.
• When two surfaces rub against each other (due to friction), mechanical energy is converted into thermal energy (heat). So, "Friction produces heat" is correct.

• Pushing a shopping cart is an example of applying a mechanical force (not related to magnetism).
• Rubbing hands together is due to friction (converting mechanical energy to heat, not magnetism).
• A large boulder falling from a cliff is due to gravity (not magnetism).
• A compass needle is a magnet. The Earth has a magnetic field, and the compass needle aligns with the Earth's magnetic field lines due to the magnetic force (an example of magnetism).

Answer:

Friction produces heat.

Second Question: