Question

The block in the figure below lies on a horizontal frictionless surface and is attached to the free end of the spring, with a spring constant of 65 N/m. Initially, the spring is at its relaxed length and the block is stationary at position x = 0. Then an applied force with a constant magnitude of 2.8 N pulls the block in the positive direction of the x axis, stretching the spring until the block stops.
Assume that the stopping point is reached.

(a) What is the position of the block?
m

(b) What is the work that has been done on the block by the applied force?
J

(c) What is the work that has been done on the block by the spring force?
J
During the block's displacement, find the following values.
(d) The block's position when its kinetic energy is maximum.
m

(e) The value of that maximum kinetic energy.
mJ

Answer 1

F = k x so x = F/k

Work done by force = U stored in spring = (1/2) k x^2

Work done by spring = -(1/2) k x^2

you let thew block go for d I assume
then the minimum U is when x = 0 and that is the maximum speed and kinetic Energy

Max KE = U at max stretch x = (1/2) k x^2