PHY 101 Mock Test 1

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.

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

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.

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

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

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

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

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

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

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).

These mathematical functions are defined as power series. Adding quantities with units like meters or seconds inside them is physically meaningless; the argument must be a pure number.

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

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

This is the definition of a perfectly elastic collision.

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

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.

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

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.

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.

The first law introduces the property of matter known as inertia, which is the tendency of an object to resist changes in its state of motion.