PHY 101 Mock Test 1

Impulse, J = ∫ F dt (or F_avg Δt for constant force), is a measure of the change in momentum it produces.

By definition, P_total = Σ (m_i * v_i) for all particles i.

θ = ω₀ t + (1/2)αt²
Explanation: This is the rotational kinematic equation, analogous to s = u t + (1/2) a t² in linear motion.

Mechanical energy is lost to heat and sound (non-conservative forces). However, when considering all forms of energy, the total energy of the universe (ball + Earth + surroundings) is conserved.

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

This is the definition of a perfectly elastic collision.

A · B = |A||B|cosθ. For θ = 90°, cos90° = 0, so the dot product is zero.

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 ball has the train’s initial horizontal velocity relative to the ground. Under gravity alone, it follows projectile motion (a parabola) as seen by the ground observer.

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

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

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.

Mechanical energy (KE+PE) is constant if the work done by all non-conservative forces (like friction) is zero.

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.

Both torque (force × distance) and energy (force × distance) have dimensions of [ML²T⁻²]. Momentum ([MLT⁻¹]) and impulse ([MLT⁻¹]) also share dimensions, but that pair is not listed together.

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).

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

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.

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

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.