Question

1. friction is a force that is always *

perpendicular to an objects motion
in the same direction as the objects motion
in the opposite direction as the objects motion

1. heat energy is also called *

thermal
sound
light
nuclear

1. according to newtons first law of motion, a moving object that is acted on by an unbalanced force will.

eventually stop
remain in motion
change its momentum
accelerate

Explanation:

• Question 4: Friction opposes the relative motion between two surfaces in contact. So, it is always in the opposite direction of an object's motion.
• Question 5: Heat energy is also known as thermal energy. Sound energy is related to vibrations, light energy is electromagnetic in nature, and nuclear energy is from nuclear reactions.
• Question 6: Newton's first law states that an object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force. But when an unbalanced force acts on a moving object, according to Newton's second law \(F = ma\) (where \(F\) is force, \(m\) is mass and \(a\) is acceleration), the object will accelerate.

Answer:

• 4. in the opposite direction as the object's motion
• 5. Thermal
• 6. accelerate