Numerade

Questions asked

BEST MATCH

QUESTION 15 In toxicology studies, LD$_{50}$ can be best described as _______. O the dose at which 50% of an exposed population develops disease O the dose at which 50% of an exposed population is killed or displays a specific symptom O the dose at which 50% of an exposed population develops a chronic effect from the toxicant O the dose in which at least 50% of the exposed population is not affected by the toxicant O the does in which more than 50% of the population dies as a result of the toxicant development

View Answer

BEST MATCH

Modelling Figure 1 shows a spacecraft with the mass $m$ approaching the surface ($S$) of a moon without an atmosphere and the gravitational acceleration $g$. To control the landing sequence a model-based controller is to be used. The task of the control system is to make the spacecraft touch down at a specified location with a controlled speed. The spacecraft can use its main (1) and reaction control system thrusters (RCS) (2-4) to control its descent. The main thruster's thrust is labelled $F_1$ and has a start-up behaviour given by $\bar{F}_1 = 0.5(u_{F,1} - \bar{F}_1)$ with $u_{F,1}$ being the main thruster's control input. The thrust of each of the RCS thrusters shall be designated $F_2$-$F_4$. The RCS thrusters ramp up time is negligeable. The arrows coming out of the thrusters show the direction of their exhaust. For sim- plicity only the dimensions height $h$ and lateral displacement $x$ should be considered when modelling the system. The mass of the spacecraft shall be considered constant during the landing sequence. h 13 2 m g 4 1 S x Figure. 1: Spacecraft on final approach (a) How many states does the system need to have given the stated purpose of the control system? (b) Determine the state-space model of the system such that all positions and veloc- ities are outputs! Extend the state-space model to include the effect of gravity! (c) Draw the state-space model of the system as block diagram!

View Answer

BEST MATCH

How many grams of NaOH are needed to completely react with 65.2 grams of HBr? HBr + NaOH --> NaBr + H$_2$O

View Answer

BEST MATCH

Alex’s preferences can be represented by the utility function U(xn, xb) = 4√xn + xb. • He originally consumed 9 units of nuts and 10 units of berries. His consumption of nuts is reduced to 4 units, but he is given enough berries so that he is just as well-off as he was before. After the change, how many units of berries does Alex consume? • If you doubled the amount of each good in each bundle, you would have bundles? • Are these two bundles on the same indifference curve? What is Alex’s marginal rate of substitution, MRS(xn, xb), when he is consuming the bundle (9, 10)? (Give a numerical answer.) • Imagine the price of nuts pn = 1, and pb = 2. What is his budget if he can afford the bundle (9, 10)? Can he afford the new bundle?

View Answer

BEST MATCH

A solution of an unknown salt in methanol is found to have an osmotic pressure of 4.75 atm at 300.0 K. All that is known about the salt is that has i=3. If the solution volume is 25.00 ml and it contains 0.335 g of the unknown salt, what is the molar mass of the unknown? Use R = 0.08206 L\cdot atm/mol\cdot K. 43.8 g/mol 119. g/mol 208. g/mol 69.5 g/mol

View Answer

BEST MATCH

Assume Charlotte has the utility function, u(x1, x2) = [3(x1)^(1/3) + x2]. p1 = $4 per unit of good 1 and p2 = $1 per unit of good 2 and Charlotte’s income is m. Answer the following questions.

View Answer

BEST MATCH

6. Critical Analysis Q7 For the following question, pick the choice that best describes the scenario presented in the state of Batland. In the town of Batland, the local government is building a new bridge. However, some voters believe that the money should have been invested in local schools instead. Which of the following statements applies to this scenario? This is an example of two parties engaging in trade, and enjoying mutual gain. This is an example of market exchange that reflects all voters' preferences. The market does not allow for proportional representation of minorities. If the legislative majority decides on a particular policy, the minority must accept the policy and help pay for it, even if they strongly object.

View Answer

BEST MATCH

A shop owner has determined that the profit from the sale of x cabinets is given by the function $P(x) = 64x + \ln(4x^2 + 10)$ dollars. Find the marginal profit function $P'(x)$.

View Answer

BEST MATCH

Which has more mass, a mole of sodium atoms or a mole of chlorine atoms?

View Answer

BEST MATCH

(b) How many grams of sodium chloride per kilogram of water are present in a 2.7 m aqueous solution?

View Answer

leroy b.