xac dinh nhiet luong , bien doientanpi ,cong thay doi ap suat cua qua trinh dot nong o the tich khong doi 6kg khong khi tu nhiet do 25C den 125C

Assuming weightless pulleys and 100% efficiency, what is the minimum input force required to lift a 120 n weight using a single fixed pulley?

•• al and bert are jogging side-by-side on a trail in the woods at a speed of 0.75 m/s. suddenly al sees the end of the trail 35 m ahead and decides to speed up to reach it. he accelerates at a constant rate of 0.50 m/s2, while bert continues on at a constant speed. (a) how long does it take al to reach the end of the trail? (b) once he reaches the end of the trail, he immediately turns around and heads back along the trail with a constant speed of 0.85 m/s. how long does it take him to meet up with bert? (c) how far are they from the end of the trail when they meet?

Work out sian speed for the first 30 minutes of her journey. give your answer in km/h.