Physics

Properties of matterA rigid sphere has a valve that can be opened or closed. The sphere with the valve open is placed in boiling water in a room where the air pressure is 1.0 atm. After a long period of time has elapsed, the valve is closed.
Part A
What will be the pressure inside the sphere if it is then placed in a mixture of ice and water?
Express your answer with the appropriate units.
p2
Part B
What will be the pressure inside the sphere if it is then placed in an insulated box filled with dry ice?
Express your answer with the appropriate units.

Physics

Properties of matter(Figure 1) shows a lightweight plank supported at its right end by a 7.0-mm-diameter rope with a tensile strength of 6.0x 10^7 N/m².

Physics

Properties of matterWhich of the following is true for 1 mol Cu and 1 mol Au?
They have equal mass
They have equal molar mass
They have the same atomic mass
They contain the same number of atoms

Physics

Properties of matterMany diseases, including COVID-19, spread because the virus is carried by tiny particles (diameter 10 µm) suspended in air, emitted when people sneeze, cough, exhale, and talk. A recent study found that these suspended particles have an effective diffusion coefficient of 1.6 x 10-³ m²/s. We have often been advised to stay 6 feet (1.83 m) away from other people in order to reduce the likelihood of contracting COVID-19. For the given diffusion coefficient, how much time would it take for these particles to diffuse this distance? Assume 3D diffusion.

Physics

Properties of matterLarger animals have sturdier bones than smaller animals. A mouse's skeleton is only a few percent of its body weight, compared to 16% for an elephant. To see why this must be so, recall, that the stress on the femur for a man standing on one leg is 1.4% of the bone's tensile strength. Suppose we scale this man up by a factor of 10 in all dimensions, keeping the same body proportions. (Assume that a 70 kg person has a femur with a cross-section area (of the compact bone) of 4.8 x 10^-4 m², a typical value.)
Both the inside and outside diameter of the femur, the region of compact bone, will increase by a factor of 10. What will be the new cross-section area?

Physics

Properties of matterThe Achilles tendon connects the muscles in your calf to the back of your foot. When you are sprinting, your Achilles tendon alternately stretches, as you bring your weight down onto your forward foot, and contracts to push you off the ground. A 70 kg runner has an Achilles tendon that is 15 cm long with a typical 1.1 x 10-4 m² area.
By how much will the runner's Achilles tendon stretch if the maximum force on it is 8.0 times his weight, a typical value while running? Express your answer with the appropriate units.

Physics

Properties of matterA mineshaft has an ore elevator hung from a single braided cable of diameter 2.5 cm. Young's modulus of the cable is 10 x 10^10 N/m². When the cable is fully extended, the end of the cable is 400 m below the support. Part A How much does the fully extended cable stretch when 1500 kg of ore is loaded?

Physics

Properties of matterA solid rod is held fixed at one end while an 8000 N force pulls on the other end. The rod is in the shape of a cylinder with a length of 3 meters and diameter 0.9 cm. The Young's modulus for the rod is 130 GN/m².
(a) Calculate the pressure exerted on the rod.
(b) Calculate how much the rod will elongate as a result of the force.
(c) If maximum distance the rod can stretch before breaking is 1 cm, calculate the maximum force that can be applied.

Physics

Properties of matterThere is little geological activity on the terrestrial planets and icv moons.
True
False
The composition of the planets gives another clue about origins.
True
False

Physics

Properties of matterThe bulk modulus for bone is 13 GPa. (a) If a diver-in-training is put into a pressurized suit, by how much would the pressure have to be raised (in atmospheres) above atmospheric pressure to compress her bones by 0.08% of their original volume?

Physics

Properties of matterA vertical, solid steel post 30 cm in diameter and 2.5 m long is required to support a load of 8014 kg. You can ignore the weight of the post. What is the strain in the post. Ysteel == 200 GPa

Physics

Properties of matterThe bulk modulus of a material is 7.89 x 10¹¹ N/m². What fractional change in volume does a piece of this material undergo when it is subjected to a bulk stress increase of 2.94x10⁷ N/m²? Assume that the force is applied uniformly over the surface.
Round your answer to 3 decimal places.

Physics

Properties of matterThe “lead” in pencils is a graphite composition with Young's modulus of approximately 1.0x10⁹ N/m². Calculate the change in length of the lead in an automatic pencil if you tap it straight into the pencil with a force of 5.6 N. The lead is 0.51 mm in diameter and 53 mm long.
Round your answer to 5 decimal places.

Physics

Properties of matterThe bulk modulus of a material is 7.63*10¹¹ N/m². What fractional change in volume does a piece of this material undergo when it is subjected to a bulk stress increase of 5.07*10⁷ N/m²? Assume that the force is applied uniformly over the surface.

Physics

Properties of matterA hollow ball with a diameter of 3.81 cm has an average density of 0.0839 g/cm³. What force must be applied to hold it stationary while it is completely submerged under water? (Enter the magnitude in N, and select the direction from the options given.)

Physics

Properties of matterWhich of the following correctly pairs a phase of matter with its description?
Solid: Particles have no motion.
Liquid: Particles expand to fill any container in which they are placed.
Gas: Particles have higher amounts of energy than when in the liquid phase.
Liquid: Particles are more strongly attached to one another than when in the solid phase.

Physics

Properties of matterA 500 Kg crocodile rests on flat ground. The contact area between its body and the floor is 8 square meters. The pressure at the contact area must be
500 Pa
625 Pa
750 Pa
1200 Pa
1625 Pa

Physics

Properties of matterA graphene rod and a tungsten rod have the same length and diameter and are subjected to the same force. If the graphene rod stretches by 2.50 x 10 m, by what (in m) will the tungsten rod stretch? Young's modulus for graphene = 1.00 x 10¹2 N/m²; for tungsten = 3.60 x 10¹¹ N/m².

Physics

Properties of matterSteel beams are used for load bearing supports in a building. Each beam is 4.0 m long with a cross-sectional area of 7.5 x 10 m² and supports a load of 4.5 x 10¹ N. Young's modulus for steel is 210 x 10° N/m².
(a) How much compression (in mm) does each beam undergo along its length?
(b) Determine the maximum load (in N) one of these beams can support without any structural failure if the compressive strength of steel is 1.50 x 10³ N/m².

Physics

Properties of matterHow old do scientists think the Earth is?
Over 4 billion years old
4 million years old
Not older than 400, 000 years old
4,000 years old

Physics

Properties of matterBars A and B are attached to a wall on the left and pulled with equal forces to the right. Bar B, with the same length and twice the radius of bar A, stretches half as far as bar A. What is the relationship between the Young's modulus for each of these materials?
A) EA = EB
B) EA = 2EB
C) EA = EB/2
D) EA = 4EB
E) EA = EB/4

Physics

Properties of matterA rod of cross-section S = 100 cm² is held between two fixed solid walls 1m apart. The temperature of one wall is then raised, and a constant heat flux Q = 0.5 W is established in the rod. What is the pressure (in 10^8 Pa) exerted on the rod if the initial stress in the rod was zero? The thermal conductivity of the rod is k = 0.2 W/m K, the linear expansion coefficient is a = 2 x 10^-5/K, Young's modulus is E = 2 x 10^11 N/m².

Physics

Properties of matterA sphere of radius R has uniform density p = 3 g/cm³. If the escape velocity from the surface of sphere is 40 m/s, then value of R is nearly nx 10 km. Find value of n to nearest integer.

Physics

Properties of matterConsider a light wire of Young's modulus Y, cross-sectional area A and length L. If a constant force F, is applied at the end of the wire as shown then
(A) Elongation in wire will be (F₀L/AY)
(B) Work done by force F₀ will be (F₀²L/AY)
(C) Loss of mechanical energy is 1/2 (F₀²L/AY)
(D) Elongation in wire will be (2F₀L/AY)

Physics

Properties of matterThe deepest a WWII submarine was able to go was 450m before bursting. Calculate the net force acting on a hatch that is 1.3m x 2.5m in size.
Net Force on hatch :

Physics

Properties of matterHow do we know that the "new" comets are members of the solar system and not just interstellar objects passing near the sun?
A. They follow elliptical orbits.
B. They are too hot to be interstellar objects.
C. There are no interstellar objects as large as comets.
D. They are moving too fast to have come from interstellar space.