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Definition
| The time interval between two successive occurrences of a recurrent event or phases of an event |
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| The number of times a specified periodic phenomenon occurs within a specified interval |
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Definition
| The maximum absolute value of a periodically varying quantity |
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| distance at which a wave repeats itself |
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| The product obtained by multiplying the average value of a force by the time during which it acts. The impulse equals the change in momentum produced by the force in this time interval |
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Definition
| transfer of energy from one physical system to another |
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Definition
| a measure of how difficult it is to stop a moving object |
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| define and give examples of transverse waves |
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Definition
s waves--those waves whose direction is perpendicular to the disturbance producing it
ex. light (3x10^8m/s) |
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Term
| define and give examples of longitudinal waves |
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Definition
p waves--those whose direction is parallel to the disturbance producing it
ex. sound(344m/s) |
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Term
| Discuss resonance. give 3 examples. |
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Definition
Resonance is defined as when a system is driven or pushed at its natural frequency the amplitude of oscillation grows very large, very fast.
Ex. child on swing, troops over bridge, voice breaking a glass |
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| Discuss how standing waves are produced |
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Definition
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| why do troops break step when crossing a bridge? |
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Definition
| Bc if their foot falls match the natural frequency of the bridge it will collapse |
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Term
| Why will sound not travel in a vacuum? Will light? |
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Definition
| This is because sound is the vibration of molecules, and there is nothing in a vacuum so there are no molecules to vibrate. Light can because it only needs eletric and magnetic fields to exist, and a vacuum has such fields. |
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| A water wave has a wavelength of 12 cm and a speed of 50 cm/s. What is the wave's frequency? |
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Definition
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| Discuss Fnet=ma vs Wnet=ΔKE |
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Definition
| The Wnet equation can be derived from the Fnet equation. The Wnet equation is the 1st enery theorem, and states that network is equal to change in energy due to an object's motion. |
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Term
| Define nodes and anti-nodes. |
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Definition
A point or region of virtually zero amplitude in a periodic system
a point at which the amplitude of one of the two kinds of displacement in a standing wave has maximum value |
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Term
| what is the range of frequency of hearing for humans? |
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Definition
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Term
| Draw a wave and label the graph: T, f, A, and λ |
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Definition
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Term
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Definition
energy due to an objects motion
energy due to an objects position |
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Term
| Can an object have KE and PE at the same time? |
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Definition
| YES--mid swing there is half and half |
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Term
| Can KE cancel? Can momentum cancel? |
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Definition
No, there can never be a negative KE
Yes, it can cancel with momentum in the opposite direction |
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Term
| Why do golfers follow through and hit hard? |
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Definition
| To increase momentum, you can make change in momentum as large as possible if you increase force and increase time (i.e., swing through for a longer time and hit harder for greater force) |
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Term
| Compare and contrast energy and momentum |
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Definition
Conservation of momentum is one of two cases--increase or decrease
Conservation of energy--energy cannot be created or destroyed, only transformed. (Joule, 1850)
however, momentum is the application of kinetic energy--the equation can be used to derive the Wnet equation. |
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| A 1000-kg rocket has 40 million joules of KE. How fast is the rocket travelling? |
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Definition
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Term
| Does a tree that falls in the woods make a sounds when it strikes the ground? |
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Definition
| Yes, because sounds is mechanical energy and when the tree falls it creates waves of vibration that are sound molecules. |
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Term
| why did the tacoma bridge of wa collapse in 1940? |
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Definition
| because of resonance, the strong winds blew that the same frequency of the bridge |
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Term
| Why does a punch hurt more with a bare hand than with a boxing glove on? |
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Definition
| Because the glove works to decrease momentum of the hand, it slows down the time it takes for the hand to reach the object, so the force is less |
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Term
| A book of mass 1-kg and with speed 200 cm/s has KE=? |
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Definition
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Term
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Definition
| displacement (or height), mass, and acceleration due to gravity |
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Term
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Definition
mass and velocity
(or moment of intertia and angular acceleration--for rotational KE) |
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Term
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Definition
| No and Yes, if it has a negative height (the refrence point is above the starting position and the object is travelling down) |
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| how does one increase the momentum of a baseball? |
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Definition
| Increase force (throw harder) and increase time (follow through) |
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| What is the speed of sound in air? |
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Definition
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| what happens to an object when Wnet is performed on the object? |
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Definition
There is a change in the kinetic energy of that object.
The forces on the object that are perpendicular do not change the KE, but those in the same or opposite direction of the motion do affect KE |
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Term
| Discuss the energy tranformations involved with a skier skiing down a steep hill |
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Definition
| First, the skier is stopped at the top of the hill and has GPE=mgh. Once the skier begins down the hill the GPE is somewhat transformed into KE=1/2mv^2. At the very bottom of the hill before it flattens out, the skier has GPE=0 and all KE. Once the skier reaches the flat part, he comes to rest and once again GPE=mgh, and KE=0. |
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Term
| Write down the three energy theorems. |
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Definition
1. Wnet=ΔKE
2. MEi=MEf (no friction)
3. MElost=MEf-MEi (includes friction)
[-fΔx=MEf-MEi] |
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Term
| Why do cars have "giveable" bumpers? |
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Definition
| To decrease momentum, if the bumper gives way, then it works to increase the time for a collision which decreases the force |
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Term
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Definition
| It can speed things up or slow things down |
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Term
| Define I and rotational variables |
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Definition
Moment of inertia, resistance to an objects change in angular velocity
conservation of angular momentum, if I gets smaller, ω (angular velocity) gets larger |
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