PHY 101 Mock Test 1

Newton’s second law for a system states that the net external force equals the total mass times the acceleration of the center of mass. Internal forces cancel in pairs.

A fundamental principle is that all terms in a valid physical equation must have the same dimensions. Dimensional analysis verifies this consistency but cannot determine dimensionless constants.

The force on the bullet forward is paired with an equal and opposite force on the gun backward, causing recoil. It also illustrates conservation of momentum.

This is the operational definition: a frame where an object with no net force acting on it moves with constant velocity (or remains at rest).

It is the mass-weighted average position of all particles in the system. It can lie outside a physical object (e.g., a doughnut).

The center of mass of any system under the influence of a uniform gravitational field follows the simple parabolic trajectory of a point mass.

When vectors are opposite (180°), they subtract. The resultant magnitude is |A – B|, which is smaller than when they are at any other angle

Just as mass resists linear acceleration (F=ma), the moment of inertia (I) resists angular acceleration (τ=Iα).

The law of conservation of momentum states that the total momentum of an isolated system remains constant. Mechanical energy is only conserved if non-conservative forces do no work.

Displacement has both magnitude (distance) and direction. Temperature, mass, and time are scalars with magnitude only.

The boat’s velocity relative to the shore is the vector sum of its velocity across the river and the river’s velocity downstream. With both constant, the resultant is constant, leading to straight-line motion at an angle.

v_AB = v_A – v_B = (60 N) – (80 N) = -20 N, which is 20 km/h in the opposite direction (South).

A world line on a space-time plot shows an object’s position (space) at every moment (time).

This is the Law of Conservation of Linear Momentum: If ΣF_ext = 0, then ΔP_total = 0.

This principle asserts that the fundamental laws of motion are invariant (take the same form) for all observers moving with constant velocity relative to each other.

All points on a rigid rotating body share the same angular displacement, velocity, and acceleration. Linear quantities depend on radius (v = rω, a_c = rω²)..

An event is a fundamental concept defined by its spatial coordinates (x, y, z) and its time coordinate (t).

With no horizontal force, the horizontal component of velocity remains unchanged. The vertical acceleration is always -g downward.

This is a common point of confusion. The two forces are an interaction pair between two different bodies, so they do not cancel for a single body.

This is the definition of a perfectly elastic collision.