Physical Science
What this domain tests
Physical Science covers matter and its changes, motion and forces, energy, waves, electricity and magnetism, and basic chemical structure and reactions. Questions often require applying a relationship, interpreting a model, or distinguishing a scientific explanation from a misconception.
Core rules
- Mass is conserved in chemical reactions; atoms are rearranged, not created or destroyed.
- Newton's second law is a = F_net/m. Forces come in interacting pairs, and an object at constant velocity has zero net force.
- Energy is conserved but can transfer or transform; work and heat are energy-transfer processes.
- For waves, v = f lambda. Frequency is set by the source; speed depends on the medium.
- Chemical properties follow from atomic structure and bonding; the periodic table organizes elements by increasing atomic number and repeating patterns.
Worked example
A 2 kg cart experiences a net force of 10 N to the right. Using a = F_net/m gives a = 10 N / 2 kg = 5 m/s^2 to the right. If the cart starts from rest and the net force remains constant for 3 s, its velocity change is a t = 5 m/s^2 x 3 s = 15 m/s. The reasoning matters: use net force, not an individual applied force, and keep mass in kilograms.
Traps
Do not substitute weight for mass; weight is mg. Do not assume a moving object has a net force in its direction of motion. In energy questions, distinguish energy from force and avoid saying energy is 'used up'. For waves, changing frequency does not change wave speed in the same medium.