Question

The spring constant of the spring in the
figure is 25 N/m, and the mass of the object
is 4 kg. The spring is unstretched and the
surface is frictionless. A constant 18 N force is
applied horizontally to the object (stretching
the spring).
v0 = 0
Find the speed of the object after it has
moved a distance of 0.35 m.
Answer in units of m/s

Answer 1

the total energy is W+K=U
So it would be Fd+(.5*m*v^2)=.5*k*x^2
Plug in the numbers, 18*.35+.5*25*v^2=.5*25*.35^2
6.3+12.5*v^2=1.53125
v=sqrt0.3815 (ignore the negative)
v=0.61765m/s