Before colliding, the momentum of Block A is +15.0 kg*m/s, and Block Bis -35.0 kg*m/s. After, Block A has a momentum -12.0 kg*m/s. What is the momentum of Block B afterwards?

Answer 1

Hi Tamia! To solve this problem, start with the momentum formula.

Δp=mv.

p= momentum (kg·m/s)

m= mass (kg)

v= velocity (m/s)

What you are actually looking for here is the change in momentum, so you want to compare the final and initial momentum for Block A and Block B combined.

Δp= p_final - p_initial

Δp= (p_Af+p_Bf)- (p_Ai+p_Bi)

Δp= (m_A•v_Af + m_B•v_Bf)- (m_A•v_Ai + m_B+v_Bi)

Think about what values you have based on units, and plug in to solve for the final momentum of B, or p_Bf.

Good luck, and reach out with any questions!