Week 10:D2: Momentum in complex systems.

When a rocket expels fuel ............................

• it gains mass and gains velocity.

• it loses mass and loses velocity.

• it loses mass but gains velocity.

• it gains mass but loses velocity.

The expelled fuel carries .............

• momentum in opposite direction, while the rocket gains momentum in the same direction.

• momentum in one direction, and the rocket gains momentum in the same direction.

• momentum in one direction, while the rocket gains momentum in the opposite direction.

According to the law of conservation of momentum, the total momentum of the system ........................... must remain .....................

• (rocket only ), constant

• (rocket + expelled fuel), constant

• (rocket + expelled fuel + gasses ), constant

• ( expelled fuel only ), constant

As the rocket burns fuel and expels it ......... at high velocity, the rocket moves .............

• Forward, forward.

• backward, backward

• forward, backward,

• backward, forward.

The momentum .........by the fuel is exactly matched by the momentum .............. by the rocket

• lost, gained

• gained, gained

• lost, lost

• gained, lost

Even though the rocket’s mass ............, its velocity ................. to maintain .................momentum in the absence of external forces.

• decreases, constant, constant

• increases , increases, constant

• decreases, increases, constant

• constant, increases, constant

If the rocket initial mass is 1500 kg (including fuel) in deep space, and it expels fuel at a rate of 5 kg/s , and the rocket is initially moving at 10 m/s. What is the mass of the fuel.

• 2 kg

• 150 kg

• 0.5 kg

• 50 kg