physics
posted by joane .
A ballistic pendulum consists of a rectangular wooden block of mass 1.5 kg suspended from a ceiling. A bullet mass 0.025 kg undergoes a completely inelastic collision with the ballistic pendulum. Due to the collision the pendulum rises to a height of 45 cm. Calculate the speed with which bullet hits the pendulum.

While swinging up H = 0.45 m elevation, the block and bullet convert kinetic energy to potential energy, without heat loss. This tells you that
V = sqrt(2gH) = 2.97 m/s
is the velocity of the block and bullet just after impact.
Next, apply conservation of momentum to the inelastic bulletimpact process, assuming that the pendulum does not swing during that brief interval. Let v be the bullet speed, m the bullet mass and M be the block's mass. Momentum conservation tells you that
m v = (M + m) V
Solve for v 
CHICKEN NUGGETS = GOLDEN TAR

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