First Semester Physics

First Semester Physics - An Overview

While the emphasis of the final exam is on Chs. 7-9 and the associated labs, keep in mind that any test in physics is by nature cumulative, since you build a skill set of problem-solving strategies as you learn new material. This skill set is used over and over again as you encounter new problems. The primary skill set is the ability to recognize and solve the three major problem types: dvat, net force, conservation. The table below presents a summary of the physics of the first semester according to problem type.

Kinematics

Net Force

Conservation

Linear

Circular motion

1 dimensional

2 dimensional

Energy

Momentum

1-dimensional

constant acceleration

uniform speed in a circular path

centripetal acceleration

Falling objects
(with and without friction)

Tension force applied
at a non-zero angle to the velocity

W_ext = ΔE_sys

covers all situations so far

0 = ΔP_sys or P_i,sys = P_f,sys

assumes the net external force
on the system is 0

Momentum is a vector. Conservation
equations are required for each axis.

Accelerating elevators and
spring scales

Motion on inclined planes
(with and without friction)

Tension in strings, springs,
and ropes

Circular motion

2-dimensional

constant vertical acceleration
zero horizontal acceleration

Collisions

Connected objects (1- or 2-dimensional)

Inelastic

Elastic

ΔK does not equal 0.

Most collisions are inelastic
to some degree. Note that a
collision can conserve mom-
entum and still be inelastic.

ΔK = 0

True elastic collisions
are limited to some
collisions of elemen-
tary particles.

Useful facts involving graphs:

The slope of the tangent to a position vs. time graph is the instantaneous velocity.
The slope of the tangent to a velocity vs. time graph is the instantaneous acceleration.
The area under a velocity vs. time graph is the displacement.
The area under a force vs. displacement graph is the work.
The area under a force vs. time graph is the impulse.

Other useful relationships:

Hooke's Law
Work-energy theorem
Impulse-momentum theorem