1. As the water in a river approaches a 10.0 m vertical drop,
itsaverage speed is x m/s. As that water falls, its Kinetic
Energyincreases. The speed of the water (ased on 1 !g of mass" is
1#.$ m/s %&st efore it hits the gro&nd. 'ind the
average speed of the riverwater efore it goes over the
eeeeeedge.
. Tyronne &ses several plan!s to slide a )*0 !g piano onto
the ac!of a 000 !g pic!&p tr&c!. The ox of the pic!&p
tr&c! is +1 cm aovethe gro&nd. The plan!s are ).0 m long.
Tyronne and his &ddies exertan average force of 1*00 to slide
the piano across the plan!s ontothe ac!. The plan!s ma!e a )0
degree angle with the gro&nd andthere is 0 !m/hr wind lowing.
-ist any AT23 yo& arema!ing.
a" 4etermine the efciency of the plan!s as a simple
machine to loadthe piano.
). A 1* !g child slides, from rest, down a playgro&nd slide
that is #.0mlong, as show in the 5g&re elow. The slide ma!es a
#0o angle withthe hori6ontal. The child7s speed at the ottom
of the slide is ).18m/s. 9hat was the force of friction that the
slide was exerting on thechild:
