All Flashcards
What is a reference frame?
A viewpoint for measuring motion, affecting the direction and magnitude of physical quantities.
What is an inertial reference frame?
A reference frame that is not accelerating; it moves at constant velocity or is at rest.
Define observed velocity.
The velocity of an object as perceived from a particular reference frame, combining its actual velocity and the observer's frame velocity.
What is relative velocity?
The velocity of an object with respect to a specific observer or reference frame.
What does it mean for acceleration to be invariant in inertial frames?
Acceleration remains constant when measured from any inertial reference frame.
How do you convert measurements between reference frames?
- Determine the relative velocity of the frames. 2. Use vector addition/subtraction to adjust the measurements based on the relative velocity.
How do you determine the observed velocity?
- Identify the object's velocity. 2. Identify the velocity of the observer's frame. 3. Use vector addition or subtraction to combine the velocities.
List the steps to solve relative velocity problems in one dimension.
- Define the positive direction. 2. Assign velocities with correct signs. 3. Add or subtract velocities depending on the direction of motion.
What is the effect of changing reference frames on measured velocity?
The measured velocity of an object changes depending on the reference frame.
What is the effect of a train moving east at 20 m/s on a person walking towards the back of the train at 2 m/s relative to the ground?
The person's velocity relative to an observer standing on the ground is 18 m/s east.
What happens to the observed velocity when a car moves at 60 km/h and a train moves at 80 km/h in the same direction?
The car's velocity relative to the train is -20 km/h (it appears to move backward).
What is the effect of the river flowing east at 3 m/s on a boat traveling north across a river at 5 m/s relative to the water?
The magnitude of the boat's velocity relative to an observer on the riverbank is m/s.
What is the effect of throwing a ball vertically upward inside a train that is moving horizontally at a constant velocity according to an observer on the train?
The ball's horizontal acceleration is zero.