The energy stored in a compressed spring is called: 15. Which fuse protects a 2.5 kW, 240 V appliance? 16. What is lost during alpha decay? 17. Parallel vs. series resistance of identical resistors?

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Asked on April 14, 2026Physics

This physics problem tests your understanding of fundamental physical laws and their applications. The step-by-step solution below breaks down the problem using relevant equations and physical reasoning.

Accepted Answer · 2026-04-14T10:39:21.213Z

tahellemadenko01, let's knock this out. 14. The energy stored in a compressed spring is called: The energy stored in a compressed or stretched spring is known as elastic potential energy. The correct answer is B. B. Elastic potential energy 15. Which of the following available fuses would be suitable to protect an electric appliance rated 2.5 kW, 240 V? Step 1: Calculate the operating current (I) using the power (P) and voltage (V) rating. P = V × I I = (P)/(V) Given P = 2.5 kW = 2500 W and V = 240 V. I = 2500 W240 V I ≈ 10.417 A Step 2: Choose a fuse rating slightly higher than the operating current. A 10 A fuse would blow because the operating current is slightly above 10 A. The next available fuse rating that is higher than 10.417 A is 11 A. The correct answer is D. D. 11 A 16. When an -decay occurs, the parent nucleus loses: An alpha particle () consists of two protons and two neutrons. Therefore, during alpha decay, the parent nucleus loses two protons and two neutrons. The correct answer is B. B. Two neutrons and two protons 17. When two identical resistors are connected in parallel, their combined resistance compared to those in series will: Let the resistance of each identical resistor be R. When connected in parallel, the combined resistance (R_p) is: (1)/(R_p) = (1)/(R) + (1)/(R) = (2)/(R) R_p = (R)/(2) When connected in series, the combined resistance (R_s) is: R_s = R + R = 2R Comparing R_p to R_s, (R)/(2) is significantly smaller than 2R. Thus, the combined resistance in parallel is a decrease compared to the series combination. The correct answer is B. B. decrease 18. Which of the following units is a unit of energy? • Pascal is a unit of pressure. • Hertz is a unit of frequency. • Kilowatt-hour is a unit of energy (Power × Time). • Metres is a unit of length. The correct answer is C. C. kilowatt-hour 19. A transformer with more secondary windings than primary windings: A transformer with more secondary windings than primary windings is a step-up transformer. In a step-up transformer, the voltage is increased, and consequently, the current is decreased (assuming an ideal transformer where power is conserved). The correct answer is A. A. has a smaller secondary current 20. Which of the following metals is NOT a magnetic material? Magnetic materials are typically ferromagnetic, meaning they are strongly attracted to magnets. Iron, Cobalt, and Nickel are ferromagnetic metals. Copper is a diamagnetic material, meaning it is weakly repelled by magnetic fields and is not considered a magnetic material in the common sense. The correct answer is B. B. Copper 21. When a plastic ball is rubbed on a duster and the duster is found to have 4 net negative charges, the charge on the plastic ball will be: According to the law of conservation of charge, if the duster gains 4 negative charges (electrons), then the plastic ball must have lost 4 electrons. Losing electrons results in a positive charge. Therefore, the plastic ball will have 4 positive charges. The correct answer is B. B. 4 positive charges 22. A force of 8 N applied to a stationary trolley causes it to move with an acceleration of 10 m s⁻². The mass of the trolley is: Step 1: Use Newton's Second Law of Motion, F = m × a. Given Force (F) = 8 N and Acceleration (a) = 10 m/s². Step 2: Rearrange the formula to solve for mass (m). m = (F)/(a) m = 8 N10 m/s^2 m = 0.8 kg This is equivalent to 8 × 10^-1 kg. The correct answer is A. A. 8 × 10^-1 kg 23. Which of the graphs in Figure 3 represents uniform deceleration of an object? In a velocity-time graph, the gradient represents acceleration. • Uniform deceleration means a constant negative acceleration. • Graph A shows constant positive acceleration (velocity increasing linearly). • Graph B shows constant negative acceleration (velocity decreasing linearly). • Graph C shows increasing acceleration (velocity increasing non-linearly). • Graph D shows zero acceleration (constant velocity). The correct answer is B. B 24. A truck transporting cement takes 120 minutes to cover 80 km between Douala and Buea. If its highest speed was 90 km/h and its lowest speed 10 km/h, the average speed of the truck is: Step 1: Convert the time from minutes to hours. 120 minutes = (120)/(60) hours = 2 hours Step 2: Calculate the average speed using the total distance and total time. Average speed = Total distanceTotal time Average speed = 80 km2 hours Average speed = 40 km/h The highest and lowest speeds are additional information not needed for calculating the average speed over the entire journey. The correct answer is A. A. 40 km/h 25. A man applied a force of 500 N to pull a 50 kg bag of rice through a distance of 10 m in 5 s. The power developed by the man is: Step 1: Calculate the work done (W). W = Force

Accepted Answer · 2026-04-14T10:39:21.213Z

tahellemadenko01, let's knock this out. 14. The energy stored in a compressed spring is called: The energy stored in a compressed or stretched spring is known as elastic potential energy. The correct answer is B. B. Elastic potential energy 15. Which of the following available fuses would be suitable to protect an electric appliance rated 2.5 kW, 240 V? Step 1: Calculate the operating current (I) using the power (P) and voltage (V) rating. P = V × I I = (P)/(V) Given P = 2.5 kW = 2500 W and V = 240 V. I = 2500 W240 V I ≈ 10.417 A Step 2: Choose a fuse rating slightly higher than the operating current. A 10 A fuse would blow because the operating current is slightly above 10 A. The next available fuse rating that is higher than 10.417 A is 11 A. The correct answer is D. D. 11 A 16. When an -decay occurs, the parent nucleus loses: An alpha particle () consists of two protons and two neutrons. Therefore, during alpha decay, the parent nucleus loses two protons and two neutrons. The correct answer is B. B. Two neutrons and two protons 17. When two identical resistors are connected in parallel, their combined resistance compared to those in series will: Let the resistance of each identical resistor be R. When connected in parallel, the combined resistance (R_p) is: (1)/(R_p) = (1)/(R) + (1)/(R) = (2)/(R) R_p = (R)/(2) When connected in series, the combined resistance (R_s) is: R_s = R + R = 2R Comparing R_p to R_s, (R)/(2) is significantly smaller than 2R. Thus, the combined resistance in parallel is a decrease compared to the series combination. The correct answer is B. B. decrease 18. Which of the following units is a unit of energy? • Pascal is a unit of pressure. • Hertz is a unit of frequency. • Kilowatt-hour is a unit of energy (Power × Time). • Metres is a unit of length. The correct answer is C. C. kilowatt-hour 19. A transformer with more secondary windings than primary windings: A transformer with more secondary windings than primary windings is a step-up transformer. In a step-up transformer, the voltage is increased, and consequently, the current is decreased (assuming an ideal transformer where power is conserved). The correct answer is A. A. has a smaller secondary current 20. Which of the following metals is NOT a magnetic material? Magnetic materials are typically ferromagnetic, meaning they are strongly attracted to magnets. Iron, Cobalt, and Nickel are ferromagnetic metals. Copper is a diamagnetic material, meaning it is weakly repelled by magnetic fields and is not considered a magnetic material in the common sense. The correct answer is B. B. Copper 21. When a plastic ball is rubbed on a duster and the duster is found to have 4 net negative charges, the charge on the plastic ball will be: According to the law of conservation of charge, if the duster gains 4 negative charges (electrons), then the plastic ball must have lost 4 electrons. Losing electrons results in a positive charge. Therefore, the plastic ball will have 4 positive charges. The correct answer is B. B. 4 positive charges 22. A force of 8 N applied to a stationary trolley causes it to move with an acceleration of 10 m s⁻². The mass of the trolley is: Step 1: Use Newton's Second Law of Motion, F = m × a. Given Force (F) = 8 N and Acceleration (a) = 10 m/s². Step 2: Rearrange the formula to solve for mass (m). m = (F)/(a) m = 8 N10 m/s^2 m = 0.8 kg This is equivalent to 8 × 10^-1 kg. The correct answer is A. A. 8 × 10^-1 kg 23. Which of the graphs in Figure 3 represents uniform deceleration of an object? In a velocity-time graph, the gradient represents acceleration. • Uniform deceleration means a constant negative acceleration. • Graph A shows constant positive acceleration (velocity increasing linearly). • Graph B shows constant negative acceleration (velocity decreasing linearly). • Graph C shows increasing acceleration (velocity increasing non-linearly). • Graph D shows zero acceleration (constant velocity). The correct answer is B. B 24. A truck transporting cement takes 120 minutes to cover 80 km between Douala and Buea. If its highest speed was 90 km/h and its lowest speed 10 km/h, the average speed of the truck is: Step 1: Convert the time from minutes to hours. 120 minutes = (120)/(60) hours = 2 hours Step 2: Calculate the average speed using the total distance and total time. Average speed = Total distanceTotal time Average speed = 80 km2 hours Average speed = 40 km/h The highest and lowest speeds are additional information not needed for calculating the average speed over the entire journey. The correct answer is A. A. 40 km/h 25. A man applied a force of 500 N to pull a 50 kg bag of rice through a distance of 10 m in 5 s. The power developed by the man is: Step 1: Calculate the work done (W). W = Force

The energy stored in a compressed spring is called: 15. Which fuse protects a 2.5 kW, 240 V appliance? 16. What is lost during alpha decay? 17. Parallel vs. series resistance of identical resistors?

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The energy stored in a compressed spring is called: 15. Which fuse protects a 2.5 kW, 240 V appliance? 16. What is lost during alpha decay? 17. Parallel vs. series resistance of identical resistors?

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