Amass m is attached to a spring which is held stretched a distance x by a force f (fig. 7-28), and then released. the spring compresses, pulling the mass. assuming there is no friction, determine the speed of the mass m when the spring returns: (a) to its normal length (x = 0); (b) to half its origin inal extension (x/2).

Spring is stretched by force f to distance "x"

now here by force balance we can say

now here we will we say that energy stored in the spring will convert into kinetic energy

now solving above equation we will have

PART 2)

now for half of the extension again we can use energy conservation

now the speed is given as

answer would be d.) i hope this

explanation:

the answer would be c. motion and direction

i hope this : )