A household gadget that uses mechanical energy is a
Answer Details
A household gadget that uses mechanical energy is a device that relies on physical movement or motion to perform its intended function. Among the four options listed, all of them use mechanical energy to some extent, but the one that relies on it the most is the grinding stone.
A grinding stone is a tool that has been used for centuries to sharpen or polish objects such as knives, scissors, or axes. It is made up of two hard stones, one stationary and the other movable, which are placed in contact with each other. By rotating the movable stone, the user can apply friction to the object being sharpened, which grinds away any rough or dull edges and produces a smooth, sharp edge. This process requires physical force and movement, which is an example of mechanical energy.
The other options also use mechanical energy to some degree. For example, a toaster uses electricity to heat up metal coils, which then convert that energy into thermal energy that is used to toast bread. However, the process of inserting the bread into the toaster and pushing down the lever to start the toasting process involves physical movement, which is an example of mechanical energy. Similarly, a blender uses electrical energy to power its blades, but the user must physically turn the blender on and off and manipulate its controls, which also involves mechanical energy. A pressure cooker uses steam and pressure to cook food quickly, but its lid must be manually locked and unlocked, which is an example of mechanical energy.