A bullet of mass 4.8 g strikes a ballistic pendulum of mass 3.3 kg. The center of mass of the pendulum rises a vertical distance of 9.7 cm. Assuming that the bullet remains embedded in the pendulum, calculate the bullet's initial speed.

....I'm getting an answer of 3002.05m/s and it's saying that my answer is wrong.

1 answer

From conservation of energy followuing impact,
gH = V'^2/2
V' = 1.3795 m/s
That is the velocity of the block when it starts swinging.

From conservation of momentum prior to the impact,
mV = (m+M)V'

V = (3.3048/0.0048)*1.3795 = 949.8 m/s

That should be rounded to 950 m/s