What occurs to a massive stellar core when it begins fusing iron into heavier elements. Make sure to discuss energy released or absorbed by the reactions.

The largest tendon in the body, the Achilles tendon, connects the calf muscle to the heel bone of the foot. This tendon is typically 17.0 cm lont 6.00 mm in diameter, and has a Young's modulus of 1.35×109 Pa. If an athlete has stretched the tendon to a length of 17.9 cm, what is the tension ?, in newtons, in the tendon?

T=___________________N

An 85.4-kg climber is scaling the vertical wall of a mountain. His safety rope is made of nylon that, when stretched, behaves like a spring with a spring constant of 1.19 103 N/m. He accidentally slips and falls freely for 0.815 m before the rope runs out of slack. How much is the rope stretched when it breaks his fall and momentarily brings him to rest?

What occurs to a massive stellar core when it begins fusing iron into heavier elements. Make sure to discuss energy released or absorbed by the reactions.

A 100-W incandescent light bulb has a cylindrical tungsten filament 26.0 cm long, 0.35 mm in diameter, and with an emissivity of 0.28.

(A) What is the temperature of the filament?

(B) For what wavelength does the spectral emittance of the bulb peak?

(C) Incandescent light bulbs are not very efficient sources of visible light. Explain why this is so.

A 2690-kg spacecraft is in a circular orbit 2320 km above the surface of Mars.

How much work must the spacecraft engines perform to move the spacecraft to a circular orbit that is 4730 km above the surface?

Explain Magnetic Resonance Imaging.What is the fundamental physics concepts behind Magnetic Resonance Imaging? How does it work?

1. Find the electric field magnitude midway through the nonconducting wall of a thick-walled pipe of infinite length with inner radius w, outer radius 3w, and a uniform volumetric charge density ρ. Answer in terms of the permittivity.

2. Find the electric field strength due to two completely hollow, concentric spherical shells made of metal. The inner shell has a radius w and carries a uniform surface charge density -σ. The outer has radius 2w and uniform charge density +4σ. Answer in terms of epsilon, and find the result first at a distance r from the center (w<r<2w) and then at r' from the center (r'>2w). You may find the answers interesting.

Imagine SETI astronomers discover a world with intelligent life.  

Should we make contact? Please write a 2 paragraph response with the following structure:

Paragraph 1: Two reasons why we SHOULD make contact. Two reasons why we SHOULD NOT make contact.

Paragraph 2: Your conclusion including the basis for your judgement.

Let’s say you push the block from the bottom of the plane all the way up to the top of the plane, then let it slide back down.

11-1. While you are pushing the block up the plane, is the work done by gravity positive or negative? Why?

11-2. While you are pushing the block up the plane, is the work done by friction positive or negative? Why?

11-3. As the block slides back down the plane, is the work done by gravity positive or negative?

11-4. As the block slides back down the plane, is the work done by friction positive or negative?

11-5. What is the net work done by gravity over the entire cycle (being pushed all the way up and then sliding all the way back down)? Is it positive, negative, or zero?

11-6. What is the net work done by friction over the entire cycle (being pushed all the way up and then sliding all the way back down)? Is it positive, negative, or zero?

Discuss the physical significance of the equivalent magnetization current densities J_m and J_ms.

Can we utilize them as current sources to run a circuit? If YES/NO, why do you think so?

While exploring a castle, Exena the Exterminator is spotted by a dragon who chases her down a hallway. Exena runs into a room and attempts to swing the heavy door shut before the dragon gets her. The door is initially perpendicular to the wall, so it must be turned through 90∘ to close. The door has a height of 3.00 m and a width of 1.15 m , and its weight is 720 N . You can ignore the friction at the hinges.

If Exena applies a force of 250 N at the edge of the door and perpendicular to it, how much time does it take her to close the door?

Use 9.80 m/s2 for the acceleration due to gravity.

Strontium 38Sr90 has a half-life of 29.1 yr. It is chemically similar to calcium, enters the body through the food chain, and collects in the bones. Consequently, 38Sr90 is a particularly serious health hazard. How long (in years) will it take for 99.9488% of the 38Sr90 released in a nuclear reactor accident to disappear?

An object is 15.2 cm to the left of a lens with a focal length of 10.2 cm. A second lens of focal length 11.8 cm is 39.27 cm to the right of the first lens. The height of the object of is 2.1 cm. What is the location of the final image with respect to the second lens? What is the height of the image?

(a) Stations A and B are at the same sea surface elevation level and have a bottom depth of 2000 m. Both stations have seawater with a uniform density with respect to depth; however the seawater density at A and B are different (sA = 24.7 kg/m3 ; sB = 25.4 kg/m3 ). [A = 40o 45' N, 25o 45' W; B = 41o 5' N, 24o 45' W]

(b) Does this current vary with respect to depth ? If so, explain how it varies and why