When can work done be negative?

A. force displacement के opposite हो / Force is opposite to displacement

Step 1: Identify the concept: this is sign convention of work. Step 2: When force acts opposite to displacement work is negative such as friction. Step 3: Remember opposite force means negative work.

Step 1: concept पहचानें: यह work sign convention है। Step 2: जब force displacement के opposite direction में हो तो work negative होता है जैसे friction। Step 3: Opposite force means negative work याद रखें।