a ball (mas .40) is initially moving to the left at 30m/s. After hitting the wall, the ball is moving to the right at 20 m/s. What is the impulse of the net force on the ball during its colllision with the wall

The impulse is -20kg m/s.

Explanation:

given mass of ball =  0.4 kg

The ball is moving towards left with the initial velocity = 30m/s

The momentum in left direction P1 = mv1

= (0.4)(30)

= 12 kg m/s

The given velocity towards right = -20 m/s ( negative sign shows inverse direction)

Momentum towards right, P2 = mv2

P2 = (0.4)(-20)

P2 = -8 kg m/s

The Impulse = change in momentum

= P2 –P1

= -8-12

= -20 kg m/s

it is the second option.

vapour or gas assuming atmospheriv pressure