Exam 2 Review - Motion

The distance traveled by an object divided by the time it takes to travel that distance is called _______

• average viscosity

• average speed

• average acceleration

• negative acceleration

Answer explanation

The distance traveled by an object divided by the time taken is defined as average speed. This term quantifies how fast an object moves over a specific distance, making 'average speed' the correct choice.

What fundamental force requires incredibly close (but not direct) contact?

• Electromagnetic Force

• Gravity

• Strong Nuclear Force

• Dark Side of the Force

Answer explanation

The Strong Nuclear Force operates at very short ranges, requiring close proximity between particles like protons and neutrons, but not direct contact. It is essential for holding atomic nuclei together, unlike the other forces listed.

Tags

NGSS.MS-PS2-5

The difference between speed and velocity is that velocity includes _______

• A) weight

• B) distance.

• C) time.

• D) direction.

Answer explanation

The difference between speed and velocity is that velocity includes direction. While speed is a scalar quantity measuring how fast an object moves, velocity is a vector quantity that specifies both speed and the direction of motion.

An example of helpful friction is:

• A) Car tires and their grip.

• B) getting holes in your socks.

• C) writing on paper with a pen.

• D) scraping your knee on the floor.

Answer explanation

A) Car tires and their grip is an example of helpful friction because it allows vehicles to maintain traction on the road, enhancing safety and control while driving.

Friction is defined as the

• force that opposes motion between two surfaces that are touching.

• rate at which velocity changes.

• resistance of an object to a change in its velocity.

• speed of an object in a particular direction.

Answer explanation

Friction is the force that opposes motion between two surfaces that are touching. It acts to resist the sliding of one surface over another, making the first answer choice the correct definition of friction.

Tags

NGSS.MS-PS2-2

An object is in motion when

• the net force acting on the object is zero.

• the object changes position relative to a frame of reference.

• the objects displacement is greater than the distance traveled.

• friction occurs.

Answer explanation

An object is in motion when it changes position relative to a frame of reference. This means that motion is defined by the object's displacement, not just the forces acting on it.

Tags

NGSS.MS-PS2-2

The force that resists the initiation of sliding motion between two surfaces that are in contact and at rest

• kinetic friction

• electronic friction

• motor-active friction

• static friction

Answer explanation

Static friction is the force that prevents two surfaces from sliding against each other when at rest. It acts to resist the initiation of motion, making it the correct choice for this question.

Which is an example of balanced forces acting on an object?

• A) A kangaroo jumping

• B) Lightning McQueen turning a corner

• C) A person standing on the ground

• D) A person pushing a sofa

Answer explanation

C) A person standing on the ground is an example of balanced forces because the force of gravity pulling them down is equal to the normal force from the ground pushing them up, resulting in no net force.

What kind of acceleration is shown here?

• positive

• negative

• none

• varies

Answer explanation

The acceleration is positive because it indicates an increase in velocity over time. This means the object is speeding up, which is characteristic of positive acceleration.

What kind of acceleration is shown here?

• positive

• negative

• none

• varies

Answer explanation

The question indicates that there is no change in velocity over time, which means there is no acceleration. Therefore, the correct answer is 'none'.

Tags

NGSS.MS-PS3-1