(MS)^2 PHYSICS MIDTERM STUDY

Newton’s First Law of Motion

Every object continues in a state of rest or of uniform speed in a straight line unless acted on by a nonzero force.

Vector Quantity

A quality whose description requires both magnitude (how much) and direction (which way).

Scalar quantity

has magnitude (how much)

EX: mass, volume, speed

Resultant

The sum of two or more vectors,

Support force (normal force)

An upward force on an object that is opposite to the force of gravity.

Equilibrium

A state of no change with no net force acting

Equilibrium Test

Whether something undergoes change in motion

What was Copernicus’s proposal about the moving Earth?

Earth was moving, circulating around the Sun.

Motion is relative

Motion of objects is always described as relative to something else. For example, you walk on the road relative to Earth, but Earth is moving relative to the Sun.

Speed

The distance covered per amount of travel time.

Average Speed

The total distance covered divided by the total travel time.

Instantaneous Speed

The speed at any instant.

Acceleration

The rate at which velocity changes overtime. Average velocity divided by time interval.

Free Fall

Falling under the influence of gravity only with no air resistance. All free falling objects on Earth accelerate at the rate of 9.8 m/s squared.

Free Fall—How Fast?

The velocity acquired by an object starting from rest is velocity = acceleration x time. So under free fall, when acceleration is 10 m/s squared, the speed is 10 m/s at 1s, 20 m/s, and so on.

What did Galileo find out about the inclination of planes?

Steeper inclines result in greater accelerations.

When the incline is vertical, acceleration is at maximum, the same as that of a falling object.

When air resistance is negligible, all objects fall with the same unchanging acceleration.

Free Fall—How Far?

The distance covered by an accelerating object starting from rest is distance = (1/2) x acceleration x time. Under free fall, when acceleration is 10 m/s squared, the distance fallen is 5m after 1s, 20m after 2sm and so on,

According to Aristotle, why do stones fall?

Stones fall on the ground because they seek their natural place.

What did Galileo discover about falling objects?

Falling objects fall at the same rate with no air resistance.

What is Inertia?

Resistance to changes in motion.

Why does a rolling ball slow down?

Slows down due to friction

If two 5-N forces act in the same direction, what is the total?

10 N

Dynamic Equilibrium

Moving with constant velocity.