Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Chapter 10 Motion Section 1: Measuring Motion Observing Motion • ___________ is an object’s change in position relative to a _____________________________. • reference point = stationary object used to determine whether an object is moving • most common reference point is Earth • common reference directions include: N, S, E, W • __________________ is the change in the position of an object. • ____________________ measures the path taken. (ACTUAL path of motion) • Displacement is the ___________________________________. Displacement must always indicate ____________________. (CHANGE in position of an object) Speed and Velocity • _______________ is the distance traveled divided by the time interval during which the motion occurred. Speed describes ________________________________________. • Speed measurements involve __________ and __________. • • The SI units for speed are ________________________________________________. When an object covers equal distances in equal amounts of time, it is moving at a __________________________. • Speed can be studied with graphs and equations. • Speed can be determined from a distance-time graph. When an object’s motion is graphed by plotting distance on the y-axis and time on the x-axis, the slope of the graph is speed. • Average speed is calculated as distance divided by time. Equation for Average Speed speed = ____________ • v = ___ _____________________________________ is the speed at a given point in time. • ____________________ is the _________ of an object in a ______________________________. • Velocity describes both the speed and the direction. • Combine velocities to determine the resultant velocity. Math Example- Velocity Metal stakes are sometimes placed in glaciers to help measure a glacier’s movement. For several days in 1936, Alaska’s Black Rapids glacier surged as swiftly as 89 meters per day down the valley. Find the glacier’s velocity in m/s. Remember to include direction. A. Given: B. Unknown: C. Conversion factors? we want time in seconds!!!! 1 day = 24 hrs 1 hr = 60 min 1 min = 60 sec D. Solve: write correct formula then plug in numbers, circle answer with units. Determining Speed with a Graph *Independent Variable = ______________ = placed on _____________ *Dependent Variable = _______________ = placed on _____________ *Speed = slope = ∆y/∆x = ∆distance/ ∆time = d/t ∆ = “change” Section 2: Acceleration Acceleration and Motion • ______________________________ is the rate at which velocity changes over time. • An object accelerates if its _______, ____________________, or both change. • Acceleration can be a change in __________. • Acceleration can be a change in ____________________. • Uniform circular motion is constant acceleration. Calculating Acceleration • Acceleration is the rate at which velocity changes. • Acceleration Equation (for straight-line motion) acceleration = ________________________________ OR a = Vf - Vi t • In SI units, acceleration is measured in meters per second per second (_______) or _________. Calculating Acceleration: A flowerpot falls off a second-story windowsill. The flowerpot starts from rest and hits the sidewalk 1.5 s later with a velocity of 14.7 m/s. Find the average acceleration of the flowerpot. A. Given : B. Unknown: C. Conversion Factors? None D. Solve: write correct formula then plug in numbers, circle answer with units. Section 3: Motion and Force Balanced and Unbalanced Forces • _______________is an action exerted on a body in order to change the body’s state of rest or motion. Force has magnitude and direction. • The _________________________ is the combination of all forces acting on an object. • Objects subjected to ______________________ either do ____________ or move at ___________________. • An ________________________ must be present to cause any change in an object’s state of motion or rest. The force of Friction • _______________________ is a force that opposes motion between two surfaces that are in contact. • Friction ____________________________________________________________. • _____________________________ resists the initiation of sliding motion between two surfaces that are in contact and at rest. • _____________________________ opposes the movement of two surfaces that are in contact and are sliding over each other. • Static friction is greater than kinetic friction. • There are many different types of kinetic friction, such as sliding friction and rolling friction. • Fluid friction, such as air resistance, also opposes motion. Friction and Motion • Friction can be ____________________ or ______________________. • Friction is necessary to roll a vehicle or hold an object. • However, friction can also cause excessive heating or wear of moving parts. • Harmful friction can be ________________. • Helpful friction can be _________________.