Rocket Science
What force must a rocket overcome to launch from Earth?
Gravity
What is the part of a rocket that carries passengers, satellites, or scientific equipment called?
The payload.
What is the name for the curved path a satellite follows around a planet?
An orbit.
Which country is commonly credited with developing the earliest gunpowder rockets?
China
Which of Newton's laws explains how a rocket moves by expelling gases backward?
Newton's Third Law of Motion.
Why do many rockets have multiple stages?
To discard empty fuel tanks and engines, reducing mass and making the remaining rocket more efficient.
Why do astronauts on the International Space Station appear weightless even though Earth's gravity still affects them?
They and the station are continuously falling around Earth together.
What was the name of the first artificial satellite, launched in 1957?
Sputnik 1
Why can a rocket still accelerate in outer space even though there is no air to push against?
Because the rocket pushes exhaust gases backward, and the gases exert an equal and opposite force on the rocket.
Why does a rocket need to carry an oxidizer along with its fuel?
Because combustion requires an oxidizer, and there is little or no oxygen available in space.
If the distance between two objects increases, what happens to the gravitational force between them?
It decreases.
Who was the first human to travel into space?
Yuri Gagarin.
A rocket's engine produces constant thrust while it burns fuel. Why might its acceleration increase?
As fuel is consumed, the rocket becomes lighter, so the same net force can produce greater acceleration.
What is the purpose of the nozzle at the bottom of a rocket engine?
To accelerate and direct hot exhaust gases, helping generate thrust.
Why does a satellite need significant sideways velocity to remain in orbit?
Its sideways motion causes it to continually miss Earth's surface as gravity pulls it downward.
What was the name of the NASA mission that first landed humans on the Moon?
Apollo 11
If a rocket's upward thrust is exactly equal to its weight, what is its vertical acceleration, ignoring air resistance?
Zero. The forces are balanced, so its velocity remains constant.
Why is reaching orbit different from simply flying high above Earth?
An orbiting spacecraft needs enough sideways speed to keep falling around Earth instead of returning directly to the ground.
If a spacecraft moves into a higher circular orbit around Earth, is its orbital speed generally faster or slower?
Slower. Higher circular orbits have lower orbital speeds.
Name one major contribution of Robert Goddard to the development of modern rockets.
He successfully launched the first liquid-fueled rocket in 1926.