Question

Spacewalker Wendy is floating outside of her space shuttle  10 meters from the entrance hatch when she carelessly disconnects her tether cord while reaching for her Polaroid camera. Her total mass (body, suit, equipment [camera included], and a dangerously low oxygen tank with only 2 minutes of oxygen left) is 91 kg. Realizing her critical situation, she throws the camera (1.0 kg) with a velocity of 9.0 m/s directly away from the ship’s entry hatch. What will become of Wendy? How long will it take her to reach the shuttle?

Answer 1

Distance of Wendy from the space shuttle, d = 10 m

Mass of Wendy without camera, M = 91 - 1 = 90 kg

Mass of camera, m = 1 kg

Speed of camera away from the ship, v = 9.0 m/s

Suppose, V is the speed of Wendy.

[we will not mention the direction of speed of Wendy. The direction will be determined by the sign of the speed. If the sign is positive, then her direction of speed is in the same direction of the camera. If the sign of speed of negative then direction of Wendy will be in opposite to the camera]

Now,

Initial momentum of the system, Pi = 0

Final momentum of the system, Pf = m*v + M*V

From conservation of momentum -

Pi = Pf

=> 0 = 1*9 + 90*V

=> V = -9/90 = -0.10 m/s

So, speed of Wendy towards the ship = 0.10 m/s

Now, time taken to cover the distance, d = 10 m

t = d / 0.10 = 10 / 0.10 = 100 s (Answer)

Since, oxygen left for 2.0 minutes.

So, Wendy will survive. (Answer)