QCAA Physics Alternative Sequence Linear motion and force

Acceleration due to gravity is independent of an object's mass, so using a lighter or heavier object will not affect the experimental value or its percentage error.

While conducting more trials reduces random error and improves the reliability of the average result, it does not decrease the percentage error inherent in the individual measurements themselves.

Although a stopwatch is more precise than counting, human reaction time (typically around $0.2\text{ s}$) still introduces a massive percentage error for a short drop from eye-level (which takes only about $0.5\text{ s}$).

A circular orbit requires a negative total energy and a launch parallel to the surface at a specific orbital velocity, which is less than the escape velocity.

An elliptical orbit requires the total energy of the system to be negative, meaning the launch velocity must be strictly less than the escape velocity.

While the trajectory is indeed a parabola, an object launched at or above escape velocity will overcome the planet's gravity and never return to land.

The kinematic equation for an object falling from rest is $v^2 = 2gs$, meaning $v$ is proportional to $\sqrt{s}$. A graph of $v$ versus $s$ would result in a curve, not a straight line.

Based on the equation $v^2 = 2gs$, $v^2$ is directly proportional to $s$, not $\sqrt{s}$. Plotting $v^2$ versus $\sqrt{s}$ would result in a quadratic curve.

Since $v$ is proportional to $s^{1/2}$, $\sqrt{v}$ would be proportional to $s^{1/4}$. Plotting $\sqrt{v}$ versus $s$ would not produce a straight line.

Incorrect. This value is too low and does not follow the kinematic equation $v = \sqrt{2gh}$.

Incorrect. This velocity is incorrect; remember that the final velocity of a dropped object is independent of its mass and depends only on height and gravity.

Incorrect. This is less than the actual final velocity calculated using $v = \sqrt{2gh}$.

This is incorrect. This value might result from an algebraic error when solving the conservation of momentum equation, such as solving for $2v$ instead of $3v$.

This is incorrect. This value represents the difference in initial velocities between object X and object Y, not the final velocity of the combined object Z.

This is incorrect. This value represents the initial velocity of object X ($10 \text{ m s}^{-1} + 40 \text{ m s}^{-1}$), rather than the final velocity of object Z.

Incorrect. This value is obtained by multiplying Earth's escape velocity by $3/4$, incorrectly assuming escape velocity is proportional to $R/M$.

Incorrect. This value is obtained by multiplying Earth's escape velocity by $\sqrt{3/4}$, incorrectly assuming escape velocity is proportional to $\sqrt{R/M}$.

Incorrect. This value is obtained by multiplying Earth's escape velocity by $4/3$, incorrectly assuming escape velocity is proportional to $M/R$ instead of $\sqrt{M/R}$.

Incorrect. This value likely comes from ignoring the negative sign on the first term ($1.3(7)^2 + 203 = 266.7$ m), which falls far outside the valid uncertainty range of $127.5$ m to $151.1$ m.

Incorrect. This value is outside the valid displacement range of $127.5$ m to $151.1$ m, possibly resulting from an arithmetic error or misapplying the uncertainty values.

Incorrect. This value likely comes from forgetting to square the time variable ($-1.3(7) + 203 = 193.9$ m), placing it outside the valid range of $127.5$ m to $151.1$ m.

Incorrect. This value represents the acceleration of the object if there were no friction acting against it ($a = g \sin(35^\circ)$).

Incorrect. This result comes from incorrectly using cosine instead of sine to find the component of gravity parallel to the slope ($mg \cos(35^\circ)$).

Incorrect. This calculates the acceleration if friction were incorrectly added to the gravitational force, acting in the same direction down the slope rather than opposing the motion.

This is the threshold frequency, calculated using only the work function ($\Phi/h$), which ignores the additional energy needed for the kinetic energy of the ejected electron.

This frequency incorrectly corresponds to the difference between the kinetic energy and the work function, rather than their sum.

This frequency corresponds only to the kinetic energy of the electron ($K/h$), ignoring the energy required to overcome the metal's work function.

Incorrect. Newton's second law ($F = ma$) shows that acceleration depends on the net force, which can change over time, meaning acceleration does not have to be uniform.

Incorrect. This describes length contraction, a principle from Einstein's theory of special relativity, not classical Newtonian mechanics.

Incorrect. This describes Newton's law of universal gravitation, which is a separate physical principle from his three laws of motion.