Vật rắn có trục quay  cố định đi qua O, chịu tác dụng của các lực F1

, F2

như hình 3.30. Biết F1 = 15N; F2 =
Hình 3.28

20N;  = 150o

;  = 120o

; OA = 20
cm; OB = 10 cm. Tính mômen quay
của lực F1.

Rohit is trying to tune an instrument

The starship enterprise is caught in a time warp and spock is forced to use the primitive techniques of the 20th century to determine the specific heat capacity of an unknown mineral. the 125-g sample was heated to 96.3°c and placed into a calorimeter containing 85.9 g of water at 20.0°c. the heat capacity of the calorimeter was 14.2 j/k. the final temperature in the calorimeter was 24.5°c. what is the specific heat capacity (in j/g°c) of the mineral? enter to 4 decimal places.

Calculate a pendulums frequency of oscillation (in hz) if the pendulum completes one cycle in 0.5s.