General Physics Midterm Review

Study of Energy and matter Definition of Physics Study of Energy and matter

SI Units Mass – kilogram Time – seconds Length – meter

Metric Prefixes Kilo --- one thousand (1000) Hecto --- one hundred (100) Centi --- one hundredth (.01) Milli --- one thousandth (.001)

Significant Digits 10000 0.0000540 342.15 67.00 890.02

Significant Digits Adding and Subtracting --- go by the lowest number of digits to the right of the decimal point 67.03 – 7.045 =

Significant Digits Multiplication and Division : go by the lowest number of sig. digits (2.45 x 105)( 3.678 x 102)=

Conversions 120 kg = ______ g 54 km = _______ mm 120 m/s = ______ km/hr 53 cm = ______ m

Distance vs. Displacement Distance: scalar, add total distance traveled Displacement: vector, difference between starting and ending point

Distance vs. Displacement A person walks 10 m north, 5 m south, then 2 m north. What is the displacement? What is the distance traveled?

Graphs (General) Slope = vertical change / horizontal change Independent variable – manipulated by the experimenter, on the x-axis Quadratic graph – Parabola, smooth upward curve, y is proportional to x2 Inverse graph – hyperbola Linear graph – straight line, y and x are directly proportional

Position-time graphs Slope = velocity Constant velocity: Constant acceleration:

Position-time graph At rest: Slowing Down:

Velocity-Time Graphs Slope = acceleration Area under the curve = displacement A = l x w A =1/2bh Constant velocity:

Velocity-time graphs Constant acceleration:

Velocity V = d/t

Acceleration Change in velocity with time a = Dv/Dt Vf = Vi + at d = vit + 1/2at2

At max height, velocity is 0 Vf = -Vi (Perfect Symmetry) WGUMCD At max height, velocity is 0 Vf = -Vi (Perfect Symmetry)

Distance is proportional to t2 Free Fall Distance is proportional to t2 all objects accelerate at the same rate regardless of mass, if air resistance is ignored

Vectors Resultant vector – the sum of more than one vector, placed from the tail of the first vector to the tip of the last vector A student walks 7 m east and then 5 m south, what is the displacement? Reverse the direction of the initial vector when subtracting

Component Method X component = hcos Y component = hsin

Newton’s First Law Equilibrium – all forces on an object are balanced Fnet = 0 object is at rest or moving with a constant velocity

Newton’s Second Law F = ma Increase acceleration: decrease mass and increase Force Weight: gravitational force exerted by a body W=mg

Newton’s Second Law A snowflake falls with a force of 5 N downward, and experiences a frictional force of 2 N upward. What is the net force on the snowflake? What must the frictional force on the snowflake be to make it move with a constant speed?

Newton’s Second Law A baseball player slides into second base with a force of 25 N and experiences a frictional force of 4 N. If the player has a mass of 60 kg, what is his acceleration?

For every action there is an equal and opposite reaction Newton’s Third Law For every action there is an equal and opposite reaction

Incline planes Increasing the angle increases the acceleration and speed of an object The parallel component of the force of gravity causes an object to slide down the incline plane Fg = mg Fg perpendicular = Fgcos Fg parallel = Fgsin

Fnet = Fric + Fg parallel a = Fnet /m Incline Planes FN = -Fg perpendicular Fric = µFN Fnet = Fric + Fg parallel a = Fnet /m

Projectile Motion (general) Motion in the horizontal direction is independent of motion in the vertical direction Velocity in the horizontal direction is constant

Type I Projectile Motion dy= 1/2gt2 dx= vxt vfy = gt

Type II Projectile Motion Range increases up to 450 (max range) and then decreases after that Vix = Vi cos Viy = Vi sin Vfy = Viy + gt dy = Viy t + 1/2gt2 dx = vxt Vf = - Vi