Question

A 40.0-kg cannonball leaves a 2.00 x 10^3 kg cannon with a velocity of +8.00 x 10^1 m/s. What is the recoil velocity of the cannon? 

Answer 1

Let,

Mass of cannon be $m_e$ = 2000kg

Mass of cannon ball be $m_c$ = 40kg

Velocity of cannon ball $v_b$ = 80 m/s

Velocity of cannon = $v_c$

Using the conservation of Angular momentum

$Initial\ momentum = Final\ momentum$

$P_i = P_f$

$m_bv_b + m_cv_c = 0$

$v_c = -\dfrac{m_b}{m_c}(v_b)$

=$- \dfrac{40}{2000}\times 80$

$v_c = -1.6 m/s$