ISCI Exam 2 - Study Group
If the frequency of a certain wave is 10 Hz, its period is
0.1 s
An input force of 50 N is applied at the end of a lever to move a box that weighs 500 N a distance of 0.1 m in the air. How far must the lever be moved at the input end?
1 m
a floating leaf oscillates two complete cycles each second as a water wave passes by. what is the wave's frequency?
2 Hz
A lever is used to move an object with a weight of 20 N. What is the mechanical advantage of the lever if the effort force is 5 N?
4
The vibrations of a transverse wave move in a direction
at right angles to the direction of wave travel.
Any machine that multiplies force does so at the expense of
distance
Temperature is a measure of the total kinetic energy in a substance.
false
When you touch a cold piece of ice with your finger, energy flows
from your finger to the ice.
Compared to a giant iceberg, a hot cup of coffee has
higher temperature, but less thermal energy.
Heat energy is measured in
joules and calories.
A substance that heats up relatively quickly has a
low specific heat
If you want to move a very heavy mass with a lever,
move the fulcrum closer to the heavy mass.
An object that has kinetic energy must be
moving
A sound source of high frequency emits a high
pitch
A refrigerator
removes thermal energy from inside the refrigerator.
Enrico Caruso, a famous opera singer, is said to have made a crystal chandelier shatter with his voice. This is a demonstration of
resonance
A 50-kg sack is lifted 2 m in the same time as a 25-kg sack is lifted 4 m. The power expended in raising the 50-kg sack compared to the power used to lift the 25-kg sack is
the same
If you do work in half the time, you power output is
twice the usual power output.
A car moving at 50 km/hr skids 20 m with locked brakes. How far will the car skid with locked brakes if it is traveling at 150 km/hr?
180 m
If you exert 100 J in 50 s, your power output is
2 W
A floating leaf oscillates up and down two complete cycles in 1 second as a water wave passes by. The wave's wavelength is 10 m. What is the wave's speed?
20 m/s
A skipper on a boat notices wave crests passing the anchor chain every 5 seconds. The skipper estimates the distance between the crests is 15 m. What is the speed of the water waves?
3 m/s
In a complex pulley system, a weight of 100 newtons is being lifted with 4 supporting ropes. The ideal mechanical advantage of this system is
4
A bow is drawn so that it has 40 J of potential energy. When released, the arrow will ideally have a kinetic energy of
40 J
A 100 N weight is being moved to a vertical height of 2 m by using a ramp that is 10 m long.What is the ideal mechanical advantage of the ramp?
5
A 60 vibration per second wave travels 30 m in 1 second. Its frequency is
60 Hz and it travels at 30 m/s.
Which requires more work: lifting a 50-kg sack vertically 2 m, or lifting a 25-kg sack vertically 4 m?
Both require the same amount of work.
Ideal mechanical advantage takes into account the forces of friction.
False
The Doppler effect occurs when a source of sound moves: I. toward you. !!. away from you.
I. and II.
The higher the mechanical advantage of a simple machine, the greater the input force is multiplied.
True
Sound waves cannot travel in
a vacuum.
The vibrations of a longitudinal wave move in a direction
along the direction of wave travel.
Simple machines allow us to
change the direction of a force and multiply force.
Aluminum has a specific heat more than twice that of copper. Place equal masses of aluminum and copper wire in a flame and the one to undergo the fastest increase in temperature will be
copper
When a bimetallic bar made of copper and iron strips is heated, the bar bends toward the iron strip. The reason for this is
copper expands more than iron.
A car that travels twice as fast as another when braking to a stop will skid
four times as far.
If you stake out a plot of land with a steel tape on a hot day, the amount of land you will have will be
larger
Sand heats up faster during the day than water-filled plants and vegetation. This indicates the specific heat for sand is
less than that of plants.
An object that has potential energy may have this energy because of its
location
A sound wave is a
longitudinal wave.
Compressions and rarefactions are characteristic of
longitudinal waves.
You dip your finger into water and make waves. If you dip your finger more frequently, the wavelength of the waves
shortens
Which has greater kinetic energy, a car traveling at 30 km/hr or a car of half that mass traveling at 60 km/hr?
the 60 km/hr car
If you push an object twice as far while applying the same force, you do
twice as much work
A 1000-kg car and a 2000-kg car are hoisted the same distance in a gas station. Raising the more massive car requires
twice as much work.
Sound travels faster in air if the air is
warm
