3. Acoustics- lesson 3 - Force and friction

What does Newton's First lae state?

• Force equals mass times velocity

• For every action, there is an opposite reaction

• An object remains at rest or moves at constant speed unless acted on by a force

• Energy is conserved in closed systems

Inertia is

• A type of friction

• Resistance due to heat

• The tendency of an object to maintain its motion

• The rate of change of velocity

Which of the following is the correct SI unit of force?

• Erg

• Newton

• Dyne

• Watt

What is the formula for force?

• F = m * a

• F = m / v

• F = a / m

• F = v * t

Friction is best described as

• A form of kinetic energy

• A type of mass

• A force that oppose motion

• A scalar quantity

What happens if net force = 0?

• Object must move

• Acceleration increases

• Motion stays unchanged

• Velocity becomes zero

A 2 kg object is accelerating at 3 m/s2. What is the force?

• 6 m

• 6 N

• 1.5 N

• 3.5 kg

What is the unit of force in CGS system?

• Joule

• Newton

• Dyne

• Erg

Which factor increases friction?

• Surface roughness

• Smoother surfaces

• Lower velocity

• Lower density

A body resists changes to its motion because of

• Inertia

• Gravity

• Energy

• Friction