Unit 1b Flashcards
What is a projectile?
An object that moves by its own inertia and is only influenced by gravity.
How are projectile motion components analyzed?
Separately into horizontal (constant velocity) and vertical (constant acceleration due to gravity).
What is the acceleration due to gravity?
Downward.
What is the vertical velocity at the highest point of a projectile?
Zero.
What defines an object in free fall?
It falls under the influence of gravity alone, accelerating at.
What is terminal velocity?
The constant velocity reached when air resistance equals the weight of the object.
What does Newton’s Law of Universal Gravitation state?
Gravitational force between two masses is proportional to their masses and inversely proportional to the square of their distance.
What is the gravitational constant?
Why is gravity essential in star formation?
It compresses hydrogen molecules until fusion occurs, producing energy.
What are Einstein’s two postulates of special relativity?
- The laws of physics are the same in all inertial frames. 2. The speed of light in a vacuum is constant for all observers.
What is time dilation?
Time appears slower for a moving object relative to a stationary observer.
What is length contraction?
A moving object’s length is shorter in the direction of motion, observed by a stationary observer.
Why can’t objects travel faster than light?
As objects approach light speed, their mass increases, requiring infinite energy to accelerate further.
What is the Doppler Effect?
The change in observed frequency due to the motion of the source or observer.
How does the Doppler Effect apply to sound?
• Moving toward: Higher frequency. • Moving away: Lower frequency.
What is redshift?
The shift of light from a star or galaxy to longer wavelengths as it moves away.
What is the twin paradox?
A twin traveling near light speed ages slower than the one remaining on Earth, due to time dilation.
How is gravity used in the slingshot effect?
Spacecraft gain speed by passing close to a planet, using its gravitational field for acceleration.
Why do satellites require relativistic corrections?
Time dilation affects satellite clocks, which must be synchronized with Earth-based systems.
How is weight different from mass?
Mass is the amount of matter (kg), while weight is the force of gravity on an object (N).
What affects gravitational force between two objects?
Their masses and the distance between their centers.
