7 Someone is trying to balance a (110cm) plank with certain forces. a) Calculate the moment of the 60N force (about O), then name its type. b) Calculate the moment of the 30N force (about O), then name its type c) Will the plank balance? If not, which way will it tip? d) What extra force would be needed at (B) to balance the plank?

Awave is produced in a rope. the wave has a speed of 33 m/s and a frequency of 22 hz. what wavelength is produced?

Which best describes the first law of thermodynamics as compared to the second law of thermodynamics? a. the first law describes how thermal energy is conserved but not the direction it moves. b. the first law describes the direction thermal energy moves but not how it is conserved. c. the first law describes how thermal energy can be created but not how it can be destroyed. d. the first law describes how thermal energy can be destroyed but not how it can be created.

Why do different substances have diffrent properties