【单选题】A uniform meter stick balances on a fulcrum placed at the 40 cm mark when a weight W is placed at the 30 cm mark. What is the weight of the meter stick?
【单选题】A living room has a floor dimensions of 3.5m and 4.2m and a height of 2.4m. What is the weight of the air in the room when the air pressure is 1.0atm? What is the magnitude of the atmosphere’s downwar...