a 50 kg pitcher throws a baseball with a mass of 0.15 kg. if the ball is thrown with a positive velocity of…

a 50 kg pitcher throws a baseball with a mass of 0.15 kg. if the ball is thrown with a positive velocity of 35 m/s and there is no net force on the system, what is the velocity of the pitcher?\n-0.1 m/s\n-0.2 m/s\n-0.7 m/s\n-1.4 m/s
Answer
Explanation:
Step1: Apply conservation of momentum
Initial momentum of system is 0 (as both are at rest initially). Let the velocity of the pitcher be $v$. According to the law of conservation of momentum $m_1v_1 + m_2v_2=0$, where $m_1 = 0.15$ kg (mass of ball), $v_1 = 35$ m/s (velocity of ball), $m_2=50$ kg (mass of pitcher) and $v_2$ is the velocity of the pitcher.
Step2: Solve for $v_2$
$0.15\times35+50\times v_2 = 0$. Then $50v_2=- 0.15\times35$, and $v_2=\frac{-0.15\times35}{50}$. $v_2=\frac{- 5.25}{50}=- 0.105\approx - 0.1$ m/s.
Answer:
-0.1 m/s