Answer: 4000 kg*m/s.
Step-by-step explanation:
To calculate the total momentum before the boxes collide, we need to add the momentum of each box. The momentum of an object is defined as the product of its mass and velocity.
The momentum of the first box is:
momentum = mass * velocity
= 40 kg * (-50 m/s)
= -2000 kg*m/s
The momentum of the second box is:
momentum = mass * velocity
= 25 kg * 80 m/s
= 2000 kg*m/s
Since the first box is moving to the left and the second box is moving to the right, we need to subtract the momentum of the first box from the momentum of the second box to get the total momentum before the collision:
total momentum = momentum of box 2 - momentum of box 1
= 2000 kg*m/s - (-2000 kg*m/s)
= 4000 kg*m/s
Therefore, the total momentum before the boxes collide is 4000 kg*m/s.