A rod XY 12m long balances horizontally when pivoted at 5.5 m from the end X. when a weight 120 N is suspended at 3 m from the end Y, the rod
balance horizontally on a knife edge placed at 7.5 m from the end X. what is
the mass of the rod.

Answer: it will take   4.36 seconds to reach her average velocity 10.69 miles/hour.explanation:   we have equation of motion ,where s is the displacement, a is the acceleration, u is the initial velocity and t is the time taken.average velocity = displacement/ time taken.average velocity = 10.69 miles/hr = 10.69*1.6*1000/(60*60) = 4.75 m/s4.75 = s/ts = 4. 1we also have acceleration = 2.18 m/s², initial velocity = 0 m/sso it will take   4.36 seconds to reach her average velocity 10.69 miles/hour.

The answer is a.  i hope this