posted by Anonymous .
A rocket engine on a spacecraft of total mass 10,000kg ejected 1.4kg of hot gases every second at an average discontinuous speed of 240ms-1.
1- What was the force on the spacecraft?
2- What was the acceleration of the spacecraft?
3-If the engines were used for 30's, what was the impulse given to the spacecraft?
4- What was the change of velocity?
please help I've been thinking of how to solve it for an hour
force = rate of change of momentum
change of momentum of vehicle + change of momentum of fuel = 0
in one second:
10,000 (change of vehicle speed) = 1.4*240 = 336 kg m/s
change of vehicle momentum per second =336 kg m/s^2 = Force (answer #1)
acceleration = change of vehicle speed per second = 336*10^-4 =3.36*10^-2 m/s^2
impulse = change of momentum in 30 seconds = Force * 30
change of velocity = change of momentum / mass
so for change of momentum = 336 divided by 10,000? @Damon