An 84% efficient single pulley is used to lift a 230 kg piano 3.5 m. How much work must be input?

Four objects are being tested to see how they are affected by fluid friction. object w has a surface area of 4.5 cm2, object x has a surface area of 2.5 cm2, object y has a surface area of 6.2 cm2, and object z has a surface area of 3 cm2. which object would experience the most fluid friction?

Will you chech and finish these for me, because i am stumped with them.

Aball has an initial velocity of 3 m/s. if there is no friction, what is the highest it could roll?