A uniform metre has a mass of 90g and it's center of mass is the 50cm mark .this ruler suspended by a thread at the 70cm mark ,l balanced by a mass of weight W hanging from the 80cm mark . calculate the weight of the ruler , calculate the moment of the ruler about the 70cm mark , what is the moment of the weight W about 70cm mark

The two stars in a certain binary star system move in circular orbits. the first star, alpha, has an orbital speed of 36 km/s. the second star, beta, has an orbital speed of 12 km/s. the orbital period is 137 d. a) what is the mass of the star alpha? b) what is the mass of the star beta?

Ahot-air balloon takes off from the ground traveling vertically with a constant upward acceleration of magnitude g/4. after time interval δt, a crew member releases a ballast sandbag from the basket attached to the balloon. how many seconds does it take the sandbag to reach the ground? (express your answer in terms of δt)

Amir observes wave 1 and wave 2 crashing into each other at two different intervals. his experiments produce wave 3 and wave 4. amir records his data in a table.what is the  best  statement about the data collected in amir’s table? wave 3 resulted from destructive interference, and wave 4 resulted from constructive interference.waves 3 and 4 resulted from constructive interference.waves 3 and 4 resulted from destructive interference.wave 3 resulted from constructive interference, and wave 4 resulted from destructive interference.