physics 2
if a more efficient exhaust system design doubles the exhaust velocity of only the third stage of our rocket, what will be the top speed of the payload riding on top of the whole space vehicle?
11,500 m/s
the moon has no atmosphere, so it is possible to orbit a satellite just above the peak of the tallest lunar hill. the lunar gravity at is surface is 1/6th the earth's surface gravity. the radius of the moon is 1740 km (beware the units!). what horizontal velocity must a satellite have to skim the lunar surface in circular orbit?
1685 m/s
if the earth doubles in mass but stayed the same size, what would be the acceleration due to gravity at the surface? the dimensions of the earth as we currently know it are: mass=5.98E24kg, radius=6.38E6m and the universal gravitational constant=6.67E-11 nm2/kg2.
19.6 m/s^2
the brake system in most cars makes use of a hydraulic system. this system consists of a fluid filled tube connected at each end to a piston. assume that the piston attached to the brake pedal has a cross sectional area of one square centimeter and the piston attached to the brake pad had a cross section area of two square centimeters. when you apply a force of 10 newtons to the piston attached to the brake pedal, the force at the brake pad will be,
20 newtons
a tv broadcast satellit with a mass of 1000kg is in geostationary orbit 42,000 kilometers above the center of the earth. the mass of the earth is roughly 6x10^24 kg. (hint: make sure you convert everything to basic MKS units before you crank the numbers!) what is the force of gravity exerted on the satellite in orbit by the earth?
227N
country western songs eulogize water towers that love sick cowboys decorate with their girl friend's name in john deere green. in fact, these homely structures have much more practical mission of maintaining city water pressure. what is the magnitude of the static water pressure you will observe on a pressure gage connected to a water main street level if the municipal water system is supplied by a water tower 25 meters tall?
245,000 meters tall
very big and very small numbers are conveniently written in scientific notation. what are the correct scientific notation versions of 33.33 and -2,100
3.333x10^1 and -2.1x10^3
if the water pressure on the first floor of Gosnold Hall is 1,000,000 pascals what is the greatest velocity that water can attain when it sprays of a hose connected to the building?
31.6 m/s
a three stage rocket is often used to launch space vehicles. the first stage is capable of accelerating from 0 to 500 m/s when burdened with both upper stages and the payload. the second stage can accelerate from 0 to 2000 m/s when carrying the payload and the third stage. the small third stage can accelerate the payload from zero to 4500 m/s. how fast will the payload be travelling when all three rockets have expended their fuel?
7000 m/s
a tv broadcast satellit with a mass of 1000kg is in geostationary orbit 42,000 kilometers above the center of the earth. the mass of the earth is roughly 6x10^24 kg. (hint: make sure you convert everything to basic MKS units before you crank the numbers!) what was the force of gravity exerted on the same satellite when it sat on the launch pad in florida?
9,800 N
a toy company specializing the alaska market makes a water rocket with a 0.1kg body that contains 0.9kg of water as ice. it uses air pressure to eject the ice as a single chunk at 10m/s when the "rocket" is launched. what is the initial velocity of the plastic body when it is launched horizontally across the class room?
90 m/s
physics terms are often incorrectly used in the popular press. identify the error in this statement from the discovery channel: "dirty jobs" hero mike rowe is afraid of a shark that can bite with a force of 2,000 pounds per square inch
bite force should be specific in pounds, not per square inch
who wrote our text, "how things work"
bloomfield
the fastest types of racing cars, formula 1 and indy cars, have wings attached to them to increase the downward force on their wheels and thus increase traction. the wings generate:
both drag and lift
which fundamental law of physics provides the primary basis for bernoulli's principle that pressure and velocity can be exchanged in a flowing fluid.
conservation of energy
based on our in class discussion, we know that high quality gold jewelry will be:
denser (more mass/volume) than a cheaper alloy
one of the most effective strokes in tennis is the top spin swerve, in which the top of the ball spins away from the player who hit it. which way is the lift force on this ball directed?
downward
which of these men was not involved in the discovery of the motions of the planets?
ferguson
doubling the flow velocity in a water pipe will increase the kinetic energy of the stream by what factor?
four times
the maximum speed a practical single stage rocket can achieve is
greater than the speed of its exhaust plume but less than is required for most satellite launches
when one of the F-22 raptor fighters at langley AFB launches a rocket powered weapon, what does the missile push against to accelerate away from the airplane?
its own exhaust (3rd law)
which temperature scale has 373 degrees as the boiling point of water?
kelvin
a curve ball pitch in baseball curves because of
lift forces
at the do it yourself car was on route 17 you can have 3 minutes of "high pressure spray" to clean your vehicle. what is the pressure of the water when it hits your shiny fenders?
one atmosphere (100,000 Pa). the extra pressure from the machine was converted to velocity when the water exited the nozzle.
to make an airplane fly upside down the pilot must
point the nose of the plane slightly up to create a positive angle of attack on the "wrong" side of the wing
although a perfectly smooth golf ball (without aerodynamic dimples) will have a terribly short range its reduced lift will offer what advantage to an amateur player?
reduced sideways curving flight ("slice")
you are floating along in a hot air balloon. you look up and notice that the bottom of the balloon is open. although there is a minor loss of hot air due to the diffusion of molecules, the majority of the hot air remains inside the balloon despite this opening because:
the air pressure inside the balloon's opening is the same as the air pressure outside that opening
an astronaut is in orbit in the international space station. which of the following statements is true?
the astronaut feels weightless because both she and the station are accelerating at the same rate
why does a tennis ball not show down very quickly when hit
the fuzz causes turbulence that energizes the boundary layer of air
pure turbo jet engines are fuel hogs compared to propellers because:
the jet imparts a bigger velocity change to a smaller mass flow of air to generate thrust.
the magnitude of the gravitational force that the earth exerts on the moon is _____ the magnitude of the force that the moon exerts on the earth?
the same as
the driver of a ski boat can feel the effect of the skier's antics. when the skier turns hard to left or right, the boat slows down slightly because:
the skier increased his drag with he generated the lift needed to accelerate him from side to side
when your house was new the clean copper pipes could deliver a generous flow of water to the shower. a decade later calcium deposits have reduced the inside diameter of the pipes and the shower feels weaker because:
the water must flow faster through the smaller opening in the pipe. since it has more kinetic energy it has less available pressure potential energy to drive the shower.
archimedes principle states that the buoyant force exerted by a fluid on an object wholly or partially immersed in it is equal to:
the weight of the fluid displaced by the object
why does the front edge of a boeng 737's wing have a row very small metal fins sticking straight up from the otherwise smooth surface? think about sports balls
to energize slow moving the boundary layer and delay flow separation from the wing
commercial airliners are predominantly powered by:
turbo fan engines