phys 101 exam 2

A helium balloon has mass, yet it doesn't fall to the floor. Is there a real force pushing up on the helium balloon? A.Yes B.No

A. Yes

You are riding a bicycle and lean to the left while taking a curve at constant speed. A.The net force on you is to the left. B.The net force on you is to the right. C.The net force on you is downward, due to gravity. D.There is no net force on you.

A.The net force on you is to the left.

If a tricycle is on a sloping floor, will this rule about it being in a stable equilibrium as long as its center of gravity is above its base of support still work? A.True B.False

A.True

If there were no launch pad beneath a NASA rocket at liftoff, the upward thrust of its engines would be A.approximately unchanged B.approximately half as much C.approximately zero

A.approximately unchanged

As a planet moves in an elliptical orbit around its star, it speed is A.fastest whenit is closest to the star. B.fastest when it is furthest from the star. C.constant. D.faster as it is moving closer to the star and slower as it moves further away.

A.fastest whenit is closest to the star.

If you squeeze a closed bottle filled with water, A.the pressure increases by the same amount everywhere in the bottle. B.the pressure increases the most where you are squeezing. C.the pressure does not change. D.the pressure increases where you are squeezing and decreases at other points.

A.the pressure increases by the same amount everywhere in the bottle.

What mass has a rest energy of 100J? A: 1.1x10-15 kg B: 3x10-8 kg C: 3.3x10-7 kg D: 0.01 kg

A: 1.1x10-15 kg

What is the gravitational force that two 100 kg persons exert on each other when standing 1m apart? A: 6.672x10-7 N B: 1 N C: 6.672x10-11 N D: 10,000 N

A: 6.672x10-7 N

Suppose you are spending your weekend on roller skates trying to get momentum from somewhere. Which of the following will give you momentum in the north direction? A: Throwing your keys southward. B: Throwing your keys northward. C: Bending down and throwing your keys straight up. D: Throwing your keys northward or bending down and throwing your keys straight up.

A: Throwing your keys southward.

Aerodynamic forces consist of A: drag and lift. B: drag, lift and buoyancy. C: drag and gravity. D: lift and drop.

A: drag and lift.

As the Reynolds number decreases, A: flow is becoming more laminar. B: flow is going from being viscous dominated to inertia dominated and therefore turbulent. C: flow is slowing down. D: flow is speeding up.

A: flow is becoming more laminar.

An object is in stable equilibrium only when A: its total potential energy rises whenever it reorients. B: its total potential energy lowers whenever it reorients. C: it is not moving. D: it is moving.

A: its total potential energy rises whenever it reorients.

A curve ball in baseball curves because of A: lift forces. B: drag forces. C: gravitational forces. D: buoyant forces.

A: lift forces.

A three - wheeler is A: statically stable and dynamically unstable. B: statically unstable and dynamically stable. C: both statically and dynamically unstable. D: both statically and dynamically stable.

A: statically stable and dynamically unstable.

Fluids have viscosity because A: the atoms and molecules within the fluid interact with each other, producing internal frictional forces. B: the atoms and molecules within the fluid are heavy and hard to push.. C: molecules in fluids are long and get tangled. D: they are always in contact with some boundary.

A: the atoms and molecules within the fluid interact with each other, producing internal frictional forces.

In studying many martial arts, it is necessary to practice efficient and safe postures. One important concept related to how one should stand is that the feet should be reasonably far apart, because A: the base of support is wider, thus stabilizing the person. B: the weight on each foot will be less than when standing normally. C: the weight on each foot will be more than when standing normally. D: the friction force increases, giving the person more traction.

A: the base of support is wider, thus stabilizing the person.

For an object that sinks in a fluid, A: the weight of fluid displaced is less than its weight. B: the weight of the fluid displaced is greater than the object's weight. C: the weight of the fluid displaced equals the object's weight. D: the weight of the object becomes more than in air.

A: the weight of fluid displaced is less than its weight.

In a popular classroom demonstration, a cotton ball is placed in the bottom of a strong test tube. A plunger fits inside the tube and it makes an air - tight seal. It is then pushed down very rapidly, and the cotton flashes and burns. This happens because A: when the air was compressed its temperature increased. B: friction between the plunger and the tube ignited the cotton. C: cotton contains a pressure - sensitive substance that burns upon impact. D: it's one of those demos that nobody understands.

A: when the air was compressed its temperature increased.

How would raising the height of a sport utility vehicle affect its turning stability? A.Make it less likely to tip over B.Make it more likely to tip over C.Have no overall effect on its stability

B.Make it more likely to tip over

Pressure is A.a type of force. B.force divided by area. C.force times area D.area divided by force.

B.force divided by area.

An upright tricycle is in a stable equilibrium because tipping it A.decreases its potential energy B.increases its potential energy C.decreases its total energy D.increases its total energy

B.increases its potential energy

When you drink water through a straw, the water A.is attracted upward by your mouth B.is pushed upward by a pressure imbalance C.is suddenly weightless and rises spontaneously

B.is pushed upward by a pressure imbalance

A hot air balloon rises because A. it is lighter than air. B.its average density is less than air. C. hot air always rises. D. hot air is more buoyant than cold air. hot air always rises.

B.its average density is less than air.

If water in a level pipe begins moving faster, A.its pressure increases. B.its pressure decreases. C.its pressure is unchanged. D.its pressure may increase or decrease, depending on other factors.

B.its pressure decreases.

If water in a uniform pipe begins to flow uphill, A.its pressure increases. B.its pressure decreases. C.its speed increases. D.its speed decreases.

B.its pressure decreases.

Atmospheric pressure is about 100000 Pa. At what depth in water does this pressure double? A: 1 m B: 10 m C: 100 m D: 1000 m

B: 10 m

The relativistic momentum of a 1000 kg car moving at 0.95 times the speed of light is: A: 9.13x108 kg m/s B: 9.13x1011 kg m/s C: 3200 kg m/s D: 2.85x1011 kg m/s

B: 9.13x1011 kg m/s

Why will a rolled - up ball of aluminum foil float in water but solid aluminum will sink? A: It won't - the ball will sink. B: Due to the air inside, the average density of the ball is lower than water. C: Aluminum is less dense than water anyway. D: Water cannot get in to equalize the pressure.

B: Due to the air inside, the average density of the ball is lower than water.

At what place in or near the jet engine is gas moving the fastest relative to the flying airplane? A: In the air flowing into the engine's inlet duct. B: In the plume of exhaust gas flowing out of the engine's outlet duct. C: In the engine's turbine D: In the engine's compressor

B: In the plume of exhaust gas flowing out of the engine's outlet duct.

Why are failures in dams more likely to occur closer to the bottom of the dam? A: Water is considerably more dense at the bottom. B: Water pressure is higher at the bottom. C: The temperature is higher at the bottom. D: Water weighs more at the bottom.

B: Water pressure is higher at the bottom.

A motorcycle is A: statically stable and dynamically unstable. B: statically unstable and dynamically stable. C: both statically and dynamically unstable. D: both statically and dynamically stable.

B: statically unstable and dynamically stable.

Astronauts in the space shuttle feel weightless because A: they are so far away from the center of the Earth. B: they are in a constant state of free - fall. C: they are moving very rapidly. D: there is no atmosphere where they are.

B: they are in a constant state of free - fall.

Which of the following would cause a household fan to stall? A. The blades are too sharply angled for the speed the fan rotates. B. The fan is rotating too fast. C. (A) and (B) D. The fan is rotating too slowly and can't push the air around.

C. (A) and (B)

Rockets receive their forward propulsion through A: pushing against the ground and objects in space. B: mass conservation of the rocket and fuel. C: pushing against the exhaust. D: small aerodynamic forces.

C. pushing against the exhaust

When you approach a light source, the light from that source has a speed A.Greater than c B.Less than c C.Equal to c

C.Equal to c

The relativistic energy of a 1000 kg car moving at 0.95 times the speed of light is: A: 1000 J B: 2.8x1017 J C: 2.9x1020 J D: 9.3x1011 J

C: 2.9x1020 J

Water weighs about 10 N per liter on Earth. A 4.0 liter ball is pushed underwater on the space shuttle, where gravity was 1/10 that on Earth. What is the buoyant force on the ball? A: 1N B: 10 N C: 4 N D: 40 N

C: 4 N

How far apart would two 100 kg persons need to be so that the force they exert on each other is equal to 1N? You can assume they are point masses, having mass but no size. A: 1m B: 6.672x10-7 m C: 8.17x10-4 m D: 100 m

C: 8.17x10-4 m

When a fluid is in steady - state flow and its path bends, the pressure on the outside of the bend is always A: Equal to the pressure everywhere else in the fluid. B: Lower than the pressure on the inside of the bend. C: Higher than the pressure on the inside of the bend. D: Darned near infinite.

C: Higher than the pressure on the inside of the bend.

Compared to planets close to the sun, and based upon Kepler's third law of planetary motion, the length of the year of planets farther out from the sun are A: the same. B: less. C: larger. D: More information is necessary.

C: larger.

You are riding in a hot air balloon. You have not used the burner for some time and the balloon begins to sink. Assuming that no air is allowed to leave or enter the balloon, A: the average density of the balloon remained constant and the buoyant force on the balloon became less than its weight. B: the average density of the balloon became greater than the surrounding air and the buoyant force on the balloon remained constant. C: the average density of the balloon became greater than the surrounding air and the buoyant force on the balloon became less than its weight. D: the balloon became heavier.

C: the average density of the balloon became greater than the surrounding air and the buoyant force on the balloon became less than its weight.

For an object that is floating on a fluid, A: the weight of fluid displaced is less than its weight. B: the weight of the fluid displaced is greater than the object's weight. C: the weight of the fluid displaced equals the object's weight. D: the weight of the object becomes less than in air.

C: the weight of the fluid displaced equals the object's weight.

For an object that is neutrally buoyant in a fluid, A: the weight of fluid displaced is less than its weight. B: the weight of the fluid displaced is greater than the object's weight. C: the weight of the fluid displaced equals the object's weight. D: the object has zero weight.

C: the weight of the fluid displaced equals the object's weight.

who was the creator of a special theory of relativity?A.Kepler B.Newton C.Galileo D.Einstein

D.Einstein

The ideal gas law says A.particle density is proportional to absolute temperature. B.pressure is proportional to mass density. C.particle density and pressure are inversely proportional. D.pressure is proportional to absolute temperature.

D.pressure is proportional to absolute temperature.

The diameter of a pipe is tripled while the pressure difference across the pipe remains the same. The volume flow rate of the pipe increases by a factor of A: 3 B: 9 C: 27 D: 81

D: 81

When a fish hovers over the bottom of a lake, what forces act on it, and what is the net force? A: Lift only, for a net force up. B: Lift only, for a net force zero. C: Lift and weight, for a net force up. D: Lift and weight, for a net force zero.

D: Lift and weight, for a net force zero.

When moving, a bicycle is in a state of dynamic equilibrium due to which of the following? A: gyroscopic effects B: air resistance C: the shape of the fork D: both gyroscopic effects and the shape of the fork

D: both gyroscopic effects and the shape of the fork

A curve ball's path bends to the right as it flies toward home plate because it is experiencing an aerodynamic force to its right. One reason why the ball is experiencing this aerodynamic force is that the ball is spinning and that spin A: causes the air to flow more rapidly around the left side of the ball than around the right side of the ball. B: exerts a torque on the ball that causes its angular momentum to shift toward the left. C: exerts a torque on the ball that causes its angular momentum to shift toward the right. D: causes the air to flow more rapidly around the right side of the ball than around the left side of the ball.

D: causes the air to flow more rapidly around the right side of the ball than around the left side of the ball.

Suppose you have two containers with liquid in them. One has a density of 760 kg/m3 and the other has a density of 910 kg /m3. If an object floats in one container and sinks in the other, the density of the object A: has a value equal to the difference in densities of the two liquids. B: must have a value equal to the average densities of the two liquids. C: has a value less than 760 kg/m3 or greater than 910 kg/m3. D: has a value between 760 kg/m3 and 910 kg/m3.

D: has a value between 760 kg/m3 and 910 kg/m3.

Flowing honey is less likely to become turbulent than flowing water because A: honey's large density favors laminar flow. B: water's large viscosity favors turbulent flow. C: water's large pressure favors turbulent flow. D: honey's large viscosity favors laminar flow.

D: honey's large viscosity favors laminar flow.

A fan can be used to circulate air around a room. The pressure at the inlet side of the fan is A:less than the pressure at the outlet side and less than atmospheric pressure. B: less than the pressure at the outlet side but more than atmospheric pressure. C: equal to the pressure at the outlet side. D: more than the pressure at the outlet side.

D: more than the pressure at the outlet side.

If a golf ball were smooth rather than dimpled, it would A: travel much too far after being hit by a golf club. B: curve toward the left after being hit by the club of a right-handed golfer. C: curve toward the right after being hit by the club of a right-handed golfer. D: not travel as far after being hit by a golf club.

D: not travel as far after being hit by a golf club.

Gravity creates A: constant motion in fluids. B: lack of pressure on the top of all fluids C: uniform pressure in fluids. D: pressure gradients in fluids.

D: pressure gradients in fluids.

When driving down a level smooth road, your car tires flatten at the bottom and they nicely support the weight of your car. However when you run over a small pointed rock the tire is punctured and fails. The rock is able to puncture the tire because A: the car has much more kinetic energy when on the rock than when on the flat road and this kinetic energy becomes potential energy in the tire. B: when the car is on the rock almost all its weight is on the tire over the rock. C: the car has much more gravitational potential energy when on the rock than when on the flat road and this gravitational potential energy becomes pressure potential energy in the tire. D: the small surface area of the rock times the pressure in the tire is not enough force to support the car. Thus, the tire fails.

D: the small surface area of the rock times the pressure in the tire is not enough force to support the car. Thus, the tire fails.

The four things that affect the amount of water flowing through a hose are A: air viscosity, hose length, inlet and outlet pressures and hose diameter. B: water viscosity, hose composition, inlet and outlet pressures and hose diameter. C: water viscosity, hose length, inlet pressure and hose diameter. D: water viscosity, hose length, inlet and outlet pressures and hose diameter.

D: water viscosity, hose length, inlet and outlet pressures and hose diameter.

The maximum speed a rocket can achieve is A: the speed of light. B: the speed of sound. C: equal to the speed of its exhaust plume. D: less than the speed of its exhaust plume. E: greater than the speed of its exhaust plume but less than the speed of light.

E: greater than the speed of its exhaust plume but less than the speed of light.