A 1.60-g bullet, moving at 542 m/s, strikes a 0.249-kg piece of wood at rest on a frictionless table. The bullet sticks in the wood, and the combined mass moves slowly down the table.
(a) Find the speed of the combination after the collision.
(b) Find the kinetic energy of the bullet before the collision.
(c) Find the kinetic energy of the combination after the collision.
(d) How much kinetic energy did the bullet lose?
(e) What percent of the bullet's original kinetic energy is lost?
AP physics - Elena, Friday, May 11, 2012 at 2:28pm
m1 = 0.0016 kg, v1 = 542 m/s, m2 =0.249, v2 = 0, u = ?
(a) m1•v1 +m2•v2 = (m1+m2) •u
u = m1•v1/(m1+m2).
(b) KE1 =m1•v1²/2.
(c) KE = ((m1+m2) •u²/2
(d) ΔKE = KE1 – KE.
(e) (ΔKE/KE1) •100%
AP physics - Alica, Friday, May 11, 2012 at 7:48pm
I have never used these equations before, can you explain/ show me