If you were given the choice to make the laptop cover of steel or
polymers. Which do you prefer and why?

1. A flywheel is the shape of a sphere of radius R. Calculate the stored energy again for rotation time T and total mass M. Do not attempt to use moment of inertia or rotational mechanics, do it the way we did in class.

2. Find an exercise calorie website, and for a 70 kg person walking on a treadmill at 5 kilometers per hour, by varying the grade of the treadmill, plot the work output power (of lifting the person) vs. the fuel (food) consumption input power of the person. That is, for different grades, (% incline), find the fuel consumption in watts, and calculate the work output of the person lifting themselves against gravity, and plot work output vs. fuel consumption. Note that a 10 % grade means climbing 15 feet for every 100 feet of horizontal travel, so you will have to a little trigonometry here. What is the differential efficiency of the person, that is, for dx increase in fuel consumption, which results in dy increase in work output, the differential efficiency is dy/dx. Where does the input power that does not result in useful lifting work go?

You are designing an aircraft to fly slowly at high altitude, so you want to minimize induced drag. Which of the following statements best describes the likely shape of the wing you will design?

Review the two videos (1) “Steam Power Plant” and (2) Gas Turbine. For each one, identify at least three examples of the design for each of the following criteria:

1. Energy performance (e.g. improved efficiency, higher power output, ...)

2. Economic considerations (reduced cost)

3. Environmental considerations (reduced emissions, etc.).

* Link of video 1 - https://youtu.be/xokHLFE96h8

Click on 1st video (how a thermal power plant works)

* Link of video 2 - https://youtu.be/GF-70yncAVY

Click on industrial gas turbine working principle

Uniform internal heat generation at  q˙⁢ = 2.00 × 10⁷ W/m³ is occurring in a cylindrical nuclear reactor fuel rod of 50-mm diameter, and under steady-state conditions the temperature distribution is of the form T(r)=a+br^2, where T is in degrees Celsius and r is in meters, while a= 800 °C and b= -4.167 × 10⁵ °C/m². The fuel rod properties are k= 30 W/m·K, ρ= 1100 kg/m³, and cp= 800 J/kg·K.

Find the steady state temperature gradient, d⁢T/d⁢r, at the outer surface of the rod, in °C/m.

What is the steady state rate of heat transfer at the outer surface, in W/m?

Immediately after the sudden increase in reactor power level (at t= 0 sec), what is the temperature at the centerline?

Immediately after the sudden increase in reactor power level (at t= 0 sec), what is the time rate of temperature change, d⁢T/d⁢t, at the centerline, in °C/s?

In one or two sentences describe the corrosion failure mode. What is one visual cue to indicate corrosion? Does corrosion always necessitate part replacement?

Say that you are looking to buy a small call and want to get a very efficient car. You are trying to decide between a hybrids car and an electric car. Hyundai offers the Ioniq in a hybrid gas and an all-electric model. Compare these models by filling in the table below.

Measure 2017 Ioniq blue 2017 Ioniq electric

MPG combined (epa)

MPG city (epa)

MPG highway (epa)

CO2 produced per mile (g/mi) in Columbia, Mo Fuel cost to drive 25mi ($)

Horse power (hp)

Torque (ft-lbf)

Range (mi)

Which would you buy and why?

1. A 150-kg sewing machine operates at 1200 RPM and has a rotating unbalance of 0.45 kg-m. What is the max stiffness of an undamped isolator such that the force transmitted to the machine’s foundation is less than:

a) 1547

b) 2547

2. Redesign helicopter seat (i.e. find new stiffness) so that the maximum velocity experienced by the pilot is 1 mm/sec.

use matlab:

A cable of length Lc supports a beam of length Lb so that it is horizontal when the weight W is attached to the beam end. The tension force T in the cable is given by the following equation: T=(Lb*Lc*W)/(D*sqrt(Lc^2-D^2)) Where D is the distance of the cable attachment point to the beam pivot. 1. Create a function M-file that evaluates the tension T as a function of D. In this function M-file the parameters Lb, Lc, and W should be declared global. 2. Create a script M-file that creates these global variables and: a) Prompts for and accepts the following values from the Command Window : W = 400N, Lb= 5 m, and Lc = 3 m (the weight is in Newtons, and the lengths are in meters) b) Uses these values and the fminbnd function to compute and display in the Command Window the value of D that minimizes the tension, T, and the minimum tension value. c) Uses fzero to determine by how much the value of D can vary from it

Find the value of the thermal conductiviity of the following substance at the given conditions:

AISI 316 Stainless Steel at 300K

What is the density of ice at 32°F and 1 atm?

What is the density of liquid water at 32°F and 1 atm?

As pressure increases the boiling temperature of water increases or decreases?

As pressure increases the freezing temperature of water increases or decreases?

How has the fact that water expands when it freezes shaped our world?

Work is a

a) point function

b) path function

c) depends on the state

d) none of the mentioned

1A. Which equilibrium phase on the Fe-Fe

phase diagram changes to Martensite when cooled quickly enough?

A. Austenite B. Ferrite C. Bainite D. Cementite

1B. For a tapered cross section metal bar that contracts when cooled, what is the stress status when the part is quenched to room temperatures (25 pts)?

A. The edge is in compression and the heavier section is in tension B. The edge is in tension and the heavier section is in compression C. No residual stresses will be built in the component

1C. A cylindrial carbon steel ingot is cooled from austenite temperatures to room temperatures, what is the stress status in the ingot (25 pts)?

A. The surface of the ingot is incompression and the center of theingot is in tension B. The surface of the ingot is in tension and the center is in compression C. No residual stresses will be built in the component