Physics Flashcards: Model Energy Transfer Computationally

What this deck covers

This deck focuses on Model Energy Transfer Computationally, giving you a quick way to review the definitions, rules, and examples that matter most for Physics.

How to use these flashcards

Work through these flashcards in short sessions. Try to answer each prompt before flipping the card, then revisit any cards you miss until the explanation feels automatic.

Flashcard 1: What is the elastic potential energy formula for a spring in computational energy tracking?

Answer: $U_s=\frac{1}{2}kx^2$. Elastic PE is proportional to spring constant and displacement squared.

Flashcard 2: What is the work done by a constant force parallel to the displacement?

Answer: $W=Fd$. Work equals force times distance when parallel.

Flashcard 3: What is the net work–kinetic energy relation used to compute speed changes?

Answer: $W_{\text{net}}=\Delta K$. Work-energy theorem: net work changes kinetic energy.

Flashcard 4: What is the power definition used to model energy transfer rate?

Answer: $P=\frac{\Delta E}{\Delta t}$. Power is energy transfer rate.

Flashcard 5: Find spring energy $U_s$ for $k=200\,\text{N/m}$ and $x=0.10\,\text{m}$.

Answer: $1\,\text{J}$. $U_s = \frac{1}{2}(200)(0.1)^2 = \frac{1}{2}(200)(0.01) = 1\,\text{J}$

Flashcard 6: What is the work formula for a constant force parallel to displacement?

Answer: $W=Fd$. Work equals force times distance when force is parallel to motion.

Flashcard 7: What equation relates energy transferred by heating to mass, specific heat, and temperature change?

Answer: $Q=mc\Delta T$. Heat capacity relates thermal energy to temperature change.

Flashcard 8: What is the thermal energy transfer from kinetic friction over distance $d$ on a level surface?

Answer: $E_{\text{th}}=f_k d=\mu_k N d$. Friction converts mechanical energy to thermal over distance.

Flashcard 9: Find heat $Q$ for $m=0.50\,\text{kg}$, c=4000\,\text{J/(kg\cdot ^\circ C)}, $\Delta T=2\,^\circ\text{C}$.

Answer: $4000\,\text{J}$. $Q=(0.50)(4000)(2)=4000\,\text{J}$.

Flashcard 10: Find work $W$ for $F=10\,\text{N}$, $d=5\,\text{m}$, and $\theta=60^\circ$.

Answer: $25\,\text{J}$. $W = (10)(5)\cos(60°) = 50(0.5) = 25\,\text{J}$

Flashcard 11: Find average power for $\Delta E=600\,\text{J}$ transferred in $\Delta t=3\,\text{s}$.

Answer: $200\,\text{W}$. $P = \frac{600}{3} = 200\,\text{W}$

Flashcard 12: What is the conservation of energy equation for a closed system in computational models?

Answer: $E_{\text{initial}}=E_{\text{final}}$. Energy is conserved in closed systems with no external work or heat transfer.

Flashcard 13: What is the work done by a constant force at angle $\theta$ to the displacement?

Answer: $W=Fd\cos\theta$. Cosine accounts for the component of force along displacement.

Flashcard 14: What is the kinetic energy formula used in energy-transfer calculations?

Answer: $K=\frac{1}{2}mv^2$. Kinetic energy depends on mass and velocity squared.

Flashcard 15: Identify the computational update rule for speed from kinetic energy $K$ and mass $m$.

Answer: $v=\sqrt{\frac{2K}{m}}$. Rearranged kinetic energy formula to solve for speed.

Flashcard 16: Find work $W$ for $F=10\,\text{N}$, $d=4\,\text{m}$, and $\theta=60^\circ$.

Answer: $20\,\text{J}$. $W=(10)(4)\cos(60^\circ)=(10)(4)(0.5)=20\,\text{J}$.

Flashcard 17: What is the thermal energy change formula for heating with no phase change?

Answer: $Q=mc\Delta T$. Heat transfer depends on mass, specific heat, and temperature change.

Flashcard 18: What is the work formula for a constant force at angle $\theta$ to displacement?

Answer: $W=Fd\cos\theta$. Work depends on the component of force in the direction of motion.

Flashcard 19: Identify the correct discrete update for speed from kinetic energy $K$ and mass $m$.

Answer: $v=\sqrt{\frac{2K}{m}}$. Rearranging $K=\frac{1}{2}mv^2$ to solve for velocity.

Flashcard 20: What is the energy balance statement including nonconservative work $W_{\text{nc}}$?

Answer: $\Delta K+\Delta U=W_{\text{nc}}$. Total mechanical energy change equals work done by nonconservative forces.

Flashcard 21: What is the conservation of energy statement used in computational energy-transfer models?

Answer: $E_{\text{in}}-E_{\text{out}}=\Delta E_{\text{system}}$. Energy conservation: input minus output equals system change.

Flashcard 22: Find efficiency $\eta$ if $E_{\text{in}}=200\,\text{J}$ and $E_{\text{out}}=150\,\text{J}$.

Answer: $0.75$. $\eta=\frac{150}{200}=0.75$ or 75% efficient.

Flashcard 23: What is the mechanical power relation connecting energy transfer and time?

Answer: $P=\frac{\Delta E}{\Delta t}$. Power is the rate of energy transfer.

Flashcard 24: Find $K$ for $m=2\,\text{kg}$ and $v=3\,\text{m/s}$ using $K=\frac{1}{2}mv^2$.

Answer: $9\,\text{J}$. $K = \frac{1}{2}(2)(3^2) = \frac{1}{2}(2)(9) = 9\,\text{J}$

Flashcard 25: What is the efficiency formula for an energy-transfer process in computational models?

Answer: $\eta=\frac{E_{\text{out}}}{E_{\text{in}}}$. Efficiency is the ratio of useful output to total input energy.

Flashcard 26: What is the gravitational potential energy function for two masses separated by distance $r$?

Answer: $U=-\frac{Gm_1m_2}{r}$. Negative sign indicates attractive force lowers PE as $r$ decreases.

Flashcard 27: Find $\Delta U_g$ for $m=1\,\text{kg}$, $\Delta h=5\,\text{m}$, $g=10\,\text{m/s}^2$.

Answer: $50\,\text{J}$. $\Delta U_g=(1)(10)(5)=50\,\text{J}$.

Flashcard 28: Find $\Delta U_g$ for $m=4\,\text{kg}$, $\Delta h=2\,\text{m}$, $g=10\,\text{m/s}^2$.

Answer: $80\,\text{J}$. $\Delta U_g = (4)(10)(2) = 80\,\text{J}$

Flashcard 29: Identify the correct discrete update for energy using constant power $P$ over time step $\Delta t$.

Answer: $E_{n+1}=E_n+P\Delta t$. Energy at next time step equals current energy plus power times time interval.

Flashcard 30: What is the change in gravitational potential energy near Earth?

Answer: $\Delta U_g=mg\Delta h$. Gravitational PE change is weight times height change.

Flashcard 31: What is the average power in terms of work done over a time interval?

Answer: $P=\frac{W}{\Delta t}$. Power equals work divided by time interval.

Flashcard 32: What equation updates system energy when heat $Q$ is added and work $W$ is done by the system?

Answer: $\Delta E=Q-W$. First law of thermodynamics: energy change equals heat added minus work done by system.

Flashcard 33: What is the gravitational potential energy change near Earth used in energy models?

Answer: $\Delta U_g=mg\Delta h$. Gravitational PE change is weight times height change.

Flashcard 34: Identify the computational update rule for energy using constant power over time step $\Delta t$.

Answer: $E_{\text{new}}=E_{\text{old}}+P\Delta t$. Energy increases by power times elapsed time.

Flashcard 35: What is the elastic potential energy stored in an ideal spring compressed or stretched by $x$?

Answer: $U_s=\frac{1}{2}kx^2$. Spring PE is quadratic in displacement from equilibrium.