1. You are standing perfectly still, and then you take a step forward. Before the step your momentum was zero, but afterward you have some momentum. Is the principle of conservation of momentum violated in this case? 2. Does the center of mass of a rocket in free space accelerate? Explain. Can the speed of a rocket exceed the exhaust speed of the fuel? Explain. 3. Early in the twentieth century, Robert Goddard proposed sending a rocket to the moon. Critic
1. You are standing perfectly still, and then you take a step
forward. Before the step your momentum was zero, but afterward you have some momentum. Is the principle of
conservation of momentum violated in this case?
2. Does the center of mass of a rocket in free space accelerate? Explain. Can the speed of a rocket exceed the exhaust
speed of the fuel? Explain.
3. Early in the twentieth century, Robert Goddard proposed
sending a rocket to the moon. Critics objected that in a
vacuum, such as exists between the Earth and the Moon,
the gases emitted by the rocket would have nothing to
push against to propel the rocket. According to Scientific
American (January 1975), Goddard placed a gun in a vacuum and fired a blank cartridge from it. (A blank cartridge contains no bullet and fires only the wadding and
the hot gases produced by the burning gunpowder.)
What happened when the gun was fired?
Trending now
This is a popular solution!
Step by step
Solved in 2 steps
