If the average thrust of a rocket motor is 100 Newtons and the burn time is 4 seconds, what is the total impulse?

To calculate total impulse, you multiply the average thrust of the rocket motor by the burn time. In this case, the average thrust is 100 Newtons, and the burn time is 4 seconds.

The formula for total impulse (I) is:

[ I = \text{thrust} \times \text{burn time} ]

Plugging in the values:

[ I = 100 , \text{N} \times 4 , \text{s} = 400 , \text{N-s} ]

Total impulse is expressed in Newton-seconds (N-s), which reflects the momentum imparted by the rocket motor during its burn period. In this scenario, the correct calculation results in a total impulse of 400 Newton-seconds, aligning with the first choice. Understanding this relationship is crucial in rocketry, as total impulse is a key factor in determining the performance and capability of a rocket.