A small boat is crossing a lake on a windy day. During some interval of time, the boat undergoes the given displacement Δ → r . Δr→. Δ → r = ( 3.11 m ) ^ ı + ( 2.69 m ) ^ ȷ Δr→=(3.11 m)ı^+(2.69 m)ȷ^ During the same interval of time, the wind exerts the given constant force → F F→ on the boat. → F = ( 263 N ) ^ ı − ( 131 N ) ^ ȷ F→=(263 N)ı^−(131 N)ȷ^ What is the total work done on the boat by the wind over this period of time?

Rohit is trying to tune an instrument

**urgent** roberto plans to use two transformers to reduce a voltage of 120 v to 4 v. he uses a transformer that has 300 coils in the primary winding and 50 coils in the secondary winding. he has four other transformers, as listed in the table. which transformer should roberto use to have an ending voltage of 4 v? a- w b-xc- yd- z

Uranium has two naturally occurring isotopes. 238u has a natural abundance of 99.3% and 235u has an abundance of 0.7%. it is the rarer 235u that is needed for nuclear reactors. the isotopes are separated by forming uranium hexafluoride uf6, which is a gas, then allowing it to diffuse through a series of porous membranes. 235uf6 has a slightly larger rms speed than 238uf6 and diffuses slightly faster. many repetitions of this procedure gradually separate the two isotopes. what is the ratio of the rms speed of 235uf6 to that of 238uf6? express your answer to five significant figures.