Question

7 g bullet is fired into a 124 g block that is initially at rest at the edge of a frictionless table of height 1.3 m. The bullet remains in the block, and after impact the block lands 2.2 m from the bottom of the table.

Find the initial speed of the bullet. The acceleration due to gravity is 9.8 m/s2

My work resulted in finding the final speed of the bullet to be 4.27m/s. Not sure what to do next

Answer 1

momentum is conserved

m bt * v bt = (m bt + m bk) * v bkbt

h = ½ g t² ... 1.3 = 4.9 t²
... t = .52 s

v bkbt = d / t = 2.2 m / .52 s
... v bkbt = 4.2 m/s


7 * v bt = 131 * 4.2