Conservation of Energy - AP Physics 1
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Calculate power if 60 J is used in 3 seconds.
Calculate power if 60 J is used in 3 seconds.
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Power = 20 W. Using $P = \frac{W}{t} = \frac{60}{3} = 20$ W.
Power = 20 W. Using $P = \frac{W}{t} = \frac{60}{3} = 20$ W.
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Identify the energy form of a moving car.
Identify the energy form of a moving car.
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Kinetic energy. Energy due to motion of the vehicle.
Kinetic energy. Energy due to motion of the vehicle.
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What is the energy form of light emitted by a bulb?
What is the energy form of light emitted by a bulb?
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Radiant energy. Electromagnetic energy in the form of visible light waves.
Radiant energy. Electromagnetic energy in the form of visible light waves.
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Find and correct the error: 'Energy is lost in a closed system.'
Find and correct the error: 'Energy is lost in a closed system.'
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Correct: 'Energy is transformed, not lost.'. Energy is conserved in closed systems, only transformed.
Correct: 'Energy is transformed, not lost.'. Energy is conserved in closed systems, only transformed.
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Find the power if 300 J is used in 10 seconds.
Find the power if 300 J is used in 10 seconds.
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Power = 30 W. Using $P = \frac{W}{t} = \frac{300}{10} = 30$ W.
Power = 30 W. Using $P = \frac{W}{t} = \frac{300}{10} = 30$ W.
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What is the energy form of a charged battery?
What is the energy form of a charged battery?
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Chemical potential energy. Energy stored in chemical bonds for later use.
Chemical potential energy. Energy stored in chemical bonds for later use.
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Identify an example of a non-conservative force.
Identify an example of a non-conservative force.
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Friction. Always opposes motion and converts mechanical energy to heat.
Friction. Always opposes motion and converts mechanical energy to heat.
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What is the energy form of a wound-up clock spring?
What is the energy form of a wound-up clock spring?
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Elastic potential energy. Energy stored by winding the spring mechanism.
Elastic potential energy. Energy stored by winding the spring mechanism.
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Which energy transformation occurs when a ball is thrown upwards?
Which energy transformation occurs when a ball is thrown upwards?
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Kinetic to potential energy. Ball slows down as it gains height, converting motion to position energy.
Kinetic to potential energy. Ball slows down as it gains height, converting motion to position energy.
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What is the energy transformation in a generator?
What is the energy transformation in a generator?
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Mechanical to electrical energy. Converts rotational motion into electrical energy output.
Mechanical to electrical energy. Converts rotational motion into electrical energy output.
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What is the energy conversion in a hydroelectric dam?
What is the energy conversion in a hydroelectric dam?
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Potential to kinetic to electrical energy. Water falls, spins turbines, generates electricity.
Potential to kinetic to electrical energy. Water falls, spins turbines, generates electricity.
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What does it mean for a force to be non-conservative?
What does it mean for a force to be non-conservative?
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Energy is not conserved; work depends on path. Work depends on path taken; mechanical energy decreases.
Energy is not conserved; work depends on path. Work depends on path taken; mechanical energy decreases.
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What happens to total energy in an isolated system?
What happens to total energy in an isolated system?
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It remains constant. Energy can only be transformed, never created or destroyed.
It remains constant. Energy can only be transformed, never created or destroyed.
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Define the Conservation of Mechanical Energy.
Define the Conservation of Mechanical Energy.
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Total mechanical energy is constant if only conservative forces act. When only gravity and springs act, $KE + PE$ stays constant.
Total mechanical energy is constant if only conservative forces act. When only gravity and springs act, $KE + PE$ stays constant.
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Identify the energy form of a compressed spring.
Identify the energy form of a compressed spring.
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Elastic potential energy. Energy stored when spring is compressed or stretched.
Elastic potential energy. Energy stored when spring is compressed or stretched.
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Calculate work if a 50 N force moves an object 4 m at 60°.
Calculate work if a 50 N force moves an object 4 m at 60°.
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$W = 100 \text{ J}$. Using $W = Fd\cos(60°) = (50)(4)(0.5) = 100$ J.
$W = 100 \text{ J}$. Using $W = Fd\cos(60°) = (50)(4)(0.5) = 100$ J.
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Find the kinetic energy of a 3 kg object moving at 4 m/s.
Find the kinetic energy of a 3 kg object moving at 4 m/s.
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$KE = 24 \text{ J}$. Using $KE = \frac{1}{2}mv^2 = \frac{1}{2}(3)(4^2) = 24$ J.
$KE = 24 \text{ J}$. Using $KE = \frac{1}{2}mv^2 = \frac{1}{2}(3)(4^2) = 24$ J.
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State what happens to energy in inelastic collisions.
State what happens to energy in inelastic collisions.
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Mechanical energy is not conserved. Some kinetic energy converts to heat and sound.
Mechanical energy is not conserved. Some kinetic energy converts to heat and sound.
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Calculate potential energy of a 2 kg object at height 6 m.
Calculate potential energy of a 2 kg object at height 6 m.
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$PE = 117.6 \text{ J}$. Using $PE = mgh = (2)(9.8)(6) = 117.6$ J.
$PE = 117.6 \text{ J}$. Using $PE = mgh = (2)(9.8)(6) = 117.6$ J.
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Identify the energy transformation in a pendulum.
Identify the energy transformation in a pendulum.
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Potential to kinetic and vice versa. Pendulum continuously exchanges kinetic and potential energy.
Potential to kinetic and vice versa. Pendulum continuously exchanges kinetic and potential energy.
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What is the formula for power in terms of work?
What is the formula for power in terms of work?
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$P = \frac{W}{t}$. Power equals work done divided by time taken.
$P = \frac{W}{t}$. Power equals work done divided by time taken.
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What is the potential energy formula for a spring?
What is the potential energy formula for a spring?
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$PE = \frac{1}{2}kx^2$. Energy stored in compressed or stretched springs.
$PE = \frac{1}{2}kx^2$. Energy stored in compressed or stretched springs.
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Calculate power if 60 J is used in 3 seconds.
Calculate power if 60 J is used in 3 seconds.
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Power = 20 W. Using $P = \frac{W}{t} = \frac{60}{3} = 20$ W.
Power = 20 W. Using $P = \frac{W}{t} = \frac{60}{3} = 20$ W.
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Find the mechanical energy if a system has 100 J of KE and 200 J of PE.
Find the mechanical energy if a system has 100 J of KE and 200 J of PE.
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Mechanical Energy = 300 J. Sum of kinetic and potential energies in the system.
Mechanical Energy = 300 J. Sum of kinetic and potential energies in the system.
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Calculate the elastic potential energy for $k = 200 \text{ N/m}$ and $x = 0.1 \text{ m}$.
Calculate the elastic potential energy for $k = 200 \text{ N/m}$ and $x = 0.1 \text{ m}$.
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$PE = 1 \text{ J}$. Using $PE = \frac{1}{2}kx^2 = \frac{1}{2}(200)(0.1^2) = 1$ J.
$PE = 1 \text{ J}$. Using $PE = \frac{1}{2}kx^2 = \frac{1}{2}(200)(0.1^2) = 1$ J.
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Calculate total energy if a 5 kg object at 10 m has 200 J KE.
Calculate total energy if a 5 kg object at 10 m has 200 J KE.
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Total Energy = 690 J. Using $PE = mgh = (5)(9.8)(10) = 490$ J, total = $200 + 490 = 690$ J.
Total Energy = 690 J. Using $PE = mgh = (5)(9.8)(10) = 490$ J, total = $200 + 490 = 690$ J.
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Identify the type of force that conserves mechanical energy.
Identify the type of force that conserves mechanical energy.
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Conservative force. Forces like gravity where work is path-independent.
Conservative force. Forces like gravity where work is path-independent.
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Which energy transformation occurs when a ball is thrown upwards?
Which energy transformation occurs when a ball is thrown upwards?
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Kinetic to potential energy. Ball slows down as it gains height, converting motion to position energy.
Kinetic to potential energy. Ball slows down as it gains height, converting motion to position energy.
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State the energy conservation principle.
State the energy conservation principle.
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Energy cannot be created or destroyed. First law of thermodynamics: energy is conserved in all processes.
Energy cannot be created or destroyed. First law of thermodynamics: energy is conserved in all processes.
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Find the increase in KE if work done is 150 J.
Find the increase in KE if work done is 150 J.
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Increase in KE = 150 J. Work-energy theorem: work done equals change in kinetic energy.
Increase in KE = 150 J. Work-energy theorem: work done equals change in kinetic energy.
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