Physics 試験対策

電卓プログラム

?→A:?→B:AB÷(A+B)

?→U:?→V:U V÷(U+V)

?→U:?→A:?→T:U+A T◢U T+0.5A T²

よくあるミス

1. 1high影響する配点: 2Change of state: melting, boiling, latent heat

   Arguing that using a copper cup is justified in heat transfer measurements because copper conducts heat faster.

   回避方法: State that copper is a good conductor of heat, which would significantly increase heat loss to the surroundings by conduction, making polystyrene (a good insulator) a much better choice to minimize errors.
2. 2high影響する配点: 2Force and Newton’s laws

   Assuming the tension in the string is exactly equal to the weight of the hanging mass when the system is accelerating downwards.

   回避方法: Apply Newton's Second Law: because the hanging mass accelerates downwards, there must be a net downward force, meaning weight must be greater than tension (\( mg - T = ma \)). Therefore, tension \( T \) is smaller than weight.
3. 3medium影響する配点: 2Gases: laws and kinetic theory

   Assuming a gas cylinder can completely empty its gas contents into external containers/balloons.

   回避方法: Remember that once the pressure inside the cylinder drops to equal the ambient pressure (e.g., seabed pressure or atmospheric pressure), no more gas can flow out. The volume of gas remaining in the cylinder is still \( V \) at that ambient pressure.
4. 4medium影響する配点: 2Electromagnetism & electromagnetic induction

   Believing that eddy currents can only be induced in magnetic metals like iron, rather than any conductor.

   回避方法: Explain that eddy currents are induced in any metallic conductor (such as copper or aluminium sheets) experiencing a changing magnetic flux, in accordance with Faraday's Law and Lenz's Law.
5. 5high影響する配点: 2Gases: laws and kinetic theory

   Using macroscopic arguments instead of kinetic theory to explain pressure changes in gases.

   回避方法: Always describe the microscopic behavior: state that pressure is due to molecules colliding with the walls, and link pressure changes to the average kinetic energy (speed) of molecules and their collision frequency per unit area.
6. 6medium影響する配点: 1Uniform circular motion and gravitation

   Omitting the negative sign in potential energy calculations when solving kinematics via conservation of energy.

   回避方法: For gravitational potential energy in orbits, use \( U = -\frac{GMm}{r} \) and carefully evaluate the difference: \( \Delta U = U_f - U_i \). Keep track of double negatives.