PHY 101 Mock Test 1

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

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

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.

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)..

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

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

Dimensionally: [ML⁻¹T⁻²] = [ML⁻³]ᵃ [LT⁻¹]ᵇ. Solving gives: For M: 1 = a; for L: -1 = -3a + b → b=2; for T: -2 = -b → b=2.

This is a key consequence of Einstein’s theory of special relativity. Simultaneity is not absolute but depends on the observer’s state of motion.

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.

By definition, the normal force is the component of contact force perpendicular (normal) to the surface. Its magnitude depends on the situation.

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).

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

This is the definition of a perfectly elastic collision.

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.

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

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

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.

W_net = ΔKE. This is a fundamental theorem derived from Newton’s second law, linking forces (via work) to changes in motion (via kinetic energy).

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

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