You're doing great, Wendimuu! Let's finish these physics questions. Direction II: Choose the best answer from the given alternatives and write in a capital letter. 14. A machine used 50N effort through a distance of 1m in order to lift a load of 100N through a distance of 0.4m. What is the efficiency of the machine? Step 1: Calculate the work input. $$ \text{Work input} = \text{Effort} \times \text{distance moved by effort} $$ $$ \text{Work input} = 50 \text{ N} \times 1 \text{ m} = 50 \text{ J} $$ Step 2: Calculate the work output. $$ \text{Work output} = \text{Load} \times \text{distance moved by load} $$ $$ \text{Work output} = 100 \text{ N} \times 0.4 \text{ m} = 40 \text{ J} $$ Step 3: Calculate the efficiency. $$ \text{Efficiency} = \frac{\text{Work output}}{\text{Work input}} \times 100\% $$ $$ \text{Efficiency} = \frac{40 \text{ J}}{50 \text{ J}} \times 100\% = 0.8 \times 100\% = 80\% $$ Answer: B. 80% 15. One is different from the others. A. pulley B. screw C. wedge D. car Explanation: Pulleys, screws, and wedges are all examples of simple machines. A car is a complex machine or vehicle, not a simple machine. Answer: D. car 16. When effort is between fulcrum and load, the lever class is: Explanation: Class 1 lever: Fulcrum is between the effort and the load (e.g., seesaw). Class 2 lever: Load is between the fulcrum and the effort (e.g., wheelbarrow). Class 3 lever: Effort is between the fulcrum and the load (e.g., fishing rod, tweezers). Answer: C. 3rd 17. Advantage a fixed pulley is: Explanation: A fixed pulley changes the direction of the force, making it easier to lift objects by pulling downwards instead of upwards. It does not multiply the force (its mechanical advantage is 1). Answer: D. we pull or push it up and down (This option seems to be describing the action of using it, which is to pull down to lift up. The primary advantage is changing the direction of force.) 18. What is SI-unit of power? Explanation: Watt (W) is the SI unit of power. Joule (J) is the SI unit of energy or work. Newton (N) is the SI unit of force. Meter (m) is the SI unit of length or displacement. Answer: A. watt 19. Gravitational potential energy is affected by: Explanation: The formula for gravitational potential energy is $PE = mgh$, where $m$ is mass, $g$ is acceleration due to gravity, and $h$ is height. Therefore, it is affected by mass, height, and acceleration due to gravity. Answer: B. height (Among the given options, height is a direct factor. Mass and acceleration due to gravity are also factors, but only one option can be chosen.) 20. Force x displacement = Explanation: Work done by a constant force is defined as the product of the force and the displacement in the direction of the force. Answer: B. Work That's 2 down. 3 left today — send the next one.