Question

Ann the Astronaut weighs 60 kg. She is space walking outside the space shuttle and pushes a 350-kg satellite away from the shuttle at 0.90 m/s. What speed does this give Ann as she moves toward the shuttle?

Answer 1

Concepts and reason

The concepts used to solve this problem are conservation of momentum.

Use the concept of conservation of momentum relating the mass and velocity to find the velocity of an astronaut.

First, use the conservation of momentum to find the expression for the velocity of an astronaut.

Then, use the expression relating the velocity of the astronaut, velocity of satellite, mass of astronaut and mass of satellite to find the velocity of the astronaut.

Fundamentals

The law of conservation of momentum states that,

“The momentum will remain constant no matter what until or unless external force comes into action”.

The expression for conservation of momentum is,

Here, mass of astronaut is , mass of satellite is , velocity of the astronaut is , and velocity of the satellite is .

The expression for conservation of momentum is,

Rearranging the expression for the velocity of the astronaut is,

…… (1)

From equation (1),

Substitute for , for , and for .

Ans:

The velocity of an astronaut is .

Answer 2

Momentum will be conserved as no external force is applied

m1 x v1 = m2 x v2

v1= 350x .9/60 = 5.25 m/s

Answer 3

In this case the momenta are equal and opposite. So,
disregarding minus signs that come from direction, we have: m(1) × v(1) = m(2) × v(2)
350 kg × 0.9 m/s = 60 kg × ? m/s
(350 kg × 0.9 m/s) ÷ 60 kg = ? m/s
(350 kg × 0.9 m/s) ÷ 60 kg = 5.25 m/s

Answer 4

Seems clear enuf for me.
Momentum before = momentum after
There was no mementum (with respect to the Shuttle) before, so Ann's memontum after has to be opposite the satellite's momentum after.

Momentum before = momentum after
0 = m1*v1 + m2*v2
where m1 and v1 are Ann's mass and velocity and m2 and v2 are the satellite's mass and velocity.

Answer 5

Using the conservation of momentum

0 + 0 = MV +m v

M =Mass of the satellite
m= mass of astronaut
V = speed of satellite = 0.9m/s
v = speed of astronaut

M V = - m v

- sign indicatesthe two are in opposite direction.

v = M V / m

= (350kg)(0.9m/s) /(60kg)

= 5.25m/s

Answer 6

applying conservation of momentum
60*0+350*0=350*0.90+60*v
v=-350*0.90/60=-5.25 m/sec