Question

3. Gustavo spends his weekend afternoons shooting unsuspecting blocks. On one such oc the 2.00g round he fires passes through a 400 g block and gets lodged in a second, 500g block. as shown. The velocities of each block after impact with the round are 0.750 m/s and 3.00m/s respectively. The blocks slide on a smooth surface. (a) Determine how fast the round was originally moving. (b) Find the work done by the forces responsible for slowing down the round as it travels through either block. Extra Credit: (c) Repeat (b) for the other block.

give as much detail as possible
do not answer extra credit

Answer 1

Initial Final Using conservation of Momentum: m_3 v_1 = m_1 v_2 + (m_2 + m_3) v_3 0.5 times 2 times 10^-3 times v_1 = 0.4 times 3/4 + (0.5 + 2 times 10^-3) times 3 10^-3 times v_1 = 0.3 + 1.506 v_1 = 1.806 times 10^3 m/s equation (a) work done by the forces will be the difference in Kinetic energy of the bullet. K_f - K_i = 1/2 m_3(v_1^2 - v_3^2) w_f = 1/2 times 2 times 10^-3 ((1.806 times 10^3)^2 - 3^2) = 10^-3 times (3261633) = 3.26 times 10^3 Joules equation (b)