Physics Ch 1-3

A 2000 m race is held on a 400 m oval track, so requires exactly 5 laps. From start to finish, what is the displacement of the winning runner?

0 m

Testable by accepted methods of science

By accepted methods of science, it can undergo scientific investigation

In a road rally race, you are told to drive half the trip at 25 m/s and half the trip at 35 m/s. It's not clear from the directions whether this means to drive half the time at each speed or drive half the distance at each speed. Which choice would yield the shorter travel time for the entire trip?

Driving half the time at each speed.

Which types of geometrical symmetry does a sphere have?

Reflection and rotational symmetry

What shape do we expect for a graph showing the position of a motorcycle versus time if the motorcycle is gaining speed at a constant rate?

The position versus time graph is parabolic.

In a discussion of what holds airplanes aloft, a classmate offers this hypothesis: "Airplanes are held up by an undetectable force field produced by magnets." Which word in this statement is most likely to keep the statement from satisfying the criteria for a scientific hypothesis?

Undetectable

difference between speed and velocity

Velocity has direction and speed does not. Speed is distance traveled/time and velocity is displacement/time. Speed is the absolute value of velocity

difference between position and displacement

Position is a vector that points from the origin to the location of an object. Displacement is a vector pointing from one location to another. Its value is the difference of the final and initial positions

Avogradro's constant

number of units in one mole of any substance 6.022x10^23

𝑥(𝑡) for constant acceleration is a

parabola

When a figure shows increasing space in between dots that means...

the object is speeding up

𝑥 𝑡 graphs curve if and only if

there is acceleration

magnitude

distance or quantity

Scientific Method

iterative process by which scientists endeavor to discover/construct the laws of nature.

Acceleration is a change in velocity (over time)

velocity (over time)

instantaneous vs average quantities

Instantaneous at any moment is the slope or derivative at that moment.

You hear a peal of thunder and go to the window. You then see a flash of lightning. Is it reasonable to assume that the thunder you heard caused the lightning you saw?

No: light travels much faster than sound, so you would expect to hear the thunder only after you saw the lighting.

position, velocity, and acceleration graphs

On a position-versus-time 𝑥 𝑡 graph, the 𝑥-component of velocity equals the value of the slope. On a velocity-versus time 𝑣 𝑡 graph, the displacement equals the area under the curve during the time interval

Motion on a ramp has constant

acceleration