Energy in a System
What is the unit of energy in the metric system?
Joules (J)
What process allows scientists to determine the absolute age of rocks using unstable atoms?
Radiometric dating
What do we call the theory that explains how Earth’s outer shell is broken into moving slabs?
Plate tectonic theory
What kind of electricity is created by a buildup of charges on the surface of an object?
Static electricity
What is the unit of force in the metric system?
Newtons (N)
As a roller coaster car goes down a hill, what kind of energy is increasing, and what kind is decreasing?
Kinetic energy increases (it’s speeding up)
Potential energy decreases (it’s losing height)
The total energy stays the same
What is a half life?
The time it takes for half of a radioactive substance to decay into a stable substance
What is the asthenosphere, and why is it important for plate tectonics?
The asthenosphere is a soft, plastic-like layer beneath the crust
It's heated by the core, causing convection currents
Hotter, less dense material rises — cooler, denser material sinks
These currents drive the slow movement of the tectonic plates above
What happens to like charges when they are brought near eachother?
They repel/push away from eachother
If an object has a mass of 500 grams and a volume of 250 cm³, what is its density?
2 g/cm3
A moving car has kinetic energy. What two factors determine how much kinetic energy it has?
Mass and velocity
What does the principle of superposition tell us about the relative ages of rock layers in an undisturbed sequence?
In undisturbed rock layers, the oldest layers are at the bottom, and the layers become progressively younger toward the top.
Why is the ocean floor older farther from a mid-ocean ridge?
New oceanic crust forms at the mid-ocean ridge from cooling magma. As more magma rises and solidifies, it pushes the older rock outward, away from the ridge.
What happens to the resistance in a wire when the wire is made longer — and why?
The resistance increases because the longer wire provides more material for the electrons to travel through, encountering more resistance along the way.
A block is pushed with a force of 15 newtons across a distance of 4 meters.
How much work is done on the block?
60J
A student lifts a 10 kg backpack straight up to a shelf that is 2 meters high.
How much work does the student do on the backpack?
196J
According to the principle of cross-cutting relationships, how can you tell whether a fault or igneous intrusion is younger or older than the surrounding rock layers?
A fault or igneous intrusion is always younger than the rock layers it cuts through — because the layers had to exist first for something to break or intrude through them.
How does thermal energy in the Earth’s interior lead to the movement of tectonic plates?
Thermal energy from the Earth's core heats the asthenosphere
This creates convection currents — hot, less dense material rises while cooler, denser material sinks
These slow-moving currents drag the overlying tectonic plates (the lithosphere) along with them
In a parallel circuit with three branches, what happens to the total current when a new branch with a low resistance is added?
The total resistance decreases
That’s because current has more paths to flow through
And since resistance goes down, the total current increases
A circuit runs at 3 amps of current and does 180 joules of work in 10 seconds.
What is the voltage across the circuit?
A 1,200 kg roller coaster car starts from rest at a height of 40 meters. Ignoring friction, what is its speed at the bottom of the hill?
28 m/s
A rock originally contained 200 grams of a radioactive isotope.
Today, it has 50 grams remaining.
If the half-life of the isotope is 2 million years, how old is the rock?
4 million years
Why is new oceanic crust younger near the mid-ocean ridges, and why doesn’t the Earth keep getting bigger as new crust forms?
New crust forms at mid-ocean ridges from rising magma — as it cools, it solidifies and pushes older crust away.
Crust is destroyed at subduction zones — the denser oceanic plate sinks back into the mantle and melts, keeping Earth's size constant.
A circuit contains a 12 V battery and three resistors in series with values of 2 Ω, 3 Ω, and 5 Ω.
What is the total current flowing through the circuit?
1.2 A
A circuit has a voltage of 12 volts and a current of 2 amps. What is the electrical power consumed by the circuit?
24W