What is the momentum

Question

Two carts mounted on an air track are moving toward one another. Cart 1 has a speed of 0.9 m/s and a mass of 0.46 kg. Cart 2 has a mass of 0.75 kg.

(a) If the total momentum of the system is to be zero, what is the initial speed (in m/s) of Cart 2? (Enter a number.)

 m/s

(c) Determine the system's kinetic energy (in J) in order to substantiate your answer to part (b). (Enter a number.)

 J

Answer 1

mass of cart 1 m₁ = 0.46 kg

velocity of cart 1 v₁ = 0.9 m/s

mass of cart 2 m₂ = 0.75 kg

let the velocity of cart 2 is -v₂

_{Total momentum of a system is zero}

m₁v₁ + m₂ (-v₂) = 0

m₁v₁ = m₂v₂

v_{2 =} m₁v₁/ m₂

v₂ = 0.46x0.9/0.75

v₂ = 0.552 m/s

kinetic energy of system = 1/2 m₁ v₁² + 1/2 m₂ v₂²

= 1/2 x0.46x (0.9)² + 1/2 x 0.75 x (0.552)²

= 0.1863 + 0.1142

=0.3 j