Aforce of 8 lb is required to hold a spring stretched 8 in. beyond its natural length. how much work w is done in stretching it from its natural length to 14 in. beyond its natural length?

work done=-8.166lb-ft

Explanation:

force = 8 lb       spring stretched (x)= 8 in

according to hooks law

F=-kx

k=-

k=-

k=-1 lb/in

work done=

work done=

work done=-98lb-in

1 ft =12 in

work done=

                 =-8.166lb-ft

when two balls of the different masses are dropped from equal height, they reach the ground at the same time .this is because they experience the same acceleration.

the acceleration is independent of mass.

thus when they are dropped they will always maintain the same velocity and travel the same distance (neglect air resistance of course) at the same time.

multiple allele inheritance is traits controlled by more than 2 alleles (ex: pigeons having 3 alleles of one gene govern their feather color).