A 15.0 g bullet with a speed of v = 235 m/s is fired into a block of wood that is initially at
rest on a frictionless surface. The block of wood is attached to a horizontal massless
spring with a spring constant k = 195 N/m that is initially uncompressed. The other end
of the spring is attached to a wall as shown in the figure below. The bullet becomes
imbedded in the block of wood which then compresses the spring a distance of 28.0 cm
before momentarily coming to a stop.
a) Determine the mass of the wooden block.
b) What fraction of the kinetic energy is transformed into other forms of energy
during the inelastic collision of the bullet with the wooden block?
The Attempt at a Solution
for a) is it like this:
kx = 1/2mv^2
x = 28cm
m = m of bullet + M of block
v = initial speed
and then solve for M
kx = 1/2(m + M)^2.
And 2nd question i dont know how to start.