PHY 101 Mock Test 1

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

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).

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

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

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

With negligible external torque, L = Iω is constant. Decreasing I forces ω to increase to keep the product constant.

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

It does not exchange matter or energy with its surroundings.
Explanation: An isolated system has no interactions across its boundary, no transfer of mass, heat, or work.

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 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.

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.

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 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.

Multiplying by a negative scalar (-2) scales the magnitude by 2 and reverses the direction by 180 degrees.

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

For kinetic and maximum static friction, the force depends on the normal force and the coefficient of friction, not on the apparent area of contact.

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

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)..

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.

This is the definition of a perfectly elastic collision.