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#156single-choiceverified

The following electric circuit may be used to convert an input voltage to a different output voltage to supply a load ("switched mode power supply"). The input voltage is 12V, the load draws a constant current of 2A (independent of the output voltage). The MOSFET is turned on and turned off periodically, according to a pulse width modulated (PWM) control signal. The switching frequency is 250kHz. The duty cycle (ratio of the turn on time of the MOSFET to period time) is used to control the output voltage. The switching losses of the MOSFET are neglectable. In turned on condition, the MOSFET can be assumed to have constant resistance drain to source (Rdson). The diode can be assumed to be ideal (zero forward voltage, zero switching losses, zero reverse recovery, ...). The inductor is formed by windings on a ferromagnetic core. The core reaches saturation at current values higher than those occurring during normal operation. All voltages are referenced to ground ("GND"). Which of the following statements about the circuit is true? There is only one correct statement!

FSG 2021
#158inputverified

The coupling of two rods with a tensile load of 80 kN is realized by flanges which are connected by 4 screws. All screws are oriented in the direction of the tensile load. Which screw core diameter must be at least present if the allowable tension stress is 32N/mm2? Enter the result of the screw core diameter in millimeter. Round solution to one decimal place. Enter the minimal possible ISO metric screw thread according to DIN 13-1 (Column 1, First Choice) / ISO 262 (Column 1, First Choice): (Mxx) Give your answer in the following format: screw core diameter, ISO metric screw thread. Example: if the screw core diameter is 12,3mm and the ISO metric screw thread is M12 then use 12.3, 12 as answer value.

FSG 2021
#159inputverified

The given circuit shows an implementation of a BSPD latch. Evaluate the time to trigger: transition of both inputs from Vs to 0V. State the results in milliseconds. Round to one decimal place. Evaluate the time to reset: transition of both inputs from 0V to Vs. State the results in seconds. Round to one decimal place. The following conditions are assumed: Vs = 5V R1 = 68kΩ R2 = 2.2MΩ C1 = 3.3μF ideal Diodes with constant Vf = 0.7V and Ir = 0A FETs as ideal "switches" with Vth somewhere between 1V and 4V, Rds_on = 0Ω and Ices = 0A ideal operational amplifier at least on trigger and reset cycle already occurred before the circuit has reached steady state before the input transition there is an input conditioning circuit evaluating hard braking and respective power delivery or throttle position with digital outputs which is not shown in the schematic both digital inputs have always exactly the same logical state which is either 0V, trigger conditition, or Vs, idle Give your answer in the following format: time to trigger, time to reset. Example: if the time to trigger is 1234,5ms and the time to reset is 12,3s then use 1234.5, 12.3 as answer value.

FSG 2021
#164inputverified

How much does a current-carrying aluminum wire of arbitrary length with a cross-section of 5 mm2 expand, if it consumes 16W for 1 Minute. Linear length expansion with the linear coefficient of length expansion α=23·10-6 1/K is assumed. The specific heat capacity is defined as c = 0.896 J/(gK) and the mass density as ρ=2.7g/cm3. Additional assumptions are no heat loss and a temperature well below the melting point. Enter the solution in millimeter and round to one decimal place.

FSG 2021
#165inputverified

The cat of a FSG technical inspector falls down from the fifth floor balcony (15m height to ground). The cat is oriented with its back downwards to the ground when starting to fall with no initial rotational or translational speed. Using the inertia of the tail, the cat tries to turn around the x-axis, see figure for definition, until the feet point downwards. How long does it take to turn? How long does the cat fall? The cat is assumed to have a mass of 1.5kg. The tail has an rotational moment of inertia around the x-axis of 1.125gm2, the rest of the cat without the tail has an rotational moment of inertia around the x-axis of 4.8gm2. The tail has a maximum rotational angular speed of 2π rad/s around the x-axis. It is assumed, that the tail can be accelarated in no time. The aerodynamic drag coefficient is assumed to be cw = 0.8 independently of the orientation around the x-axis. The cats aerodynamic cross sectional area is given by 0.04m2, independently of the orientation around the x-axis. The air density is assumed to be 1.2kg/m3, the gravitational accelaration is defined to be 9.9m/s2. Please enter: - the time needed until reaching the ground in seconds rounded to the nearest two decimals. - the time needed to turn on the feet in seconds rounded to the nearest two decimals. Give your answer in the following format: time needed until reaching the ground, time needed to turn on the feet. Example: if the time needed until reaching the ground is 12,34s and the time needed to turn on the feet is 23,45 then use 12.34, 23.45 as answer value.

FSG 2021
#167single-choiceverified

Time keeping has registered an uncorrected elapsed driving time of t=24,30 min for the fastest endurance vehicle and it knocked 7 cones (DOO). The lowest corrected used energy of all teams who are able to score points in efficiency is E=5,32 kWh. Our team has an endurance uncorrected elapsed driving time of t=28,20 min and we made 1 off-course (OC). Our corrected used energy is E=6,08 kWh. The best efficiency team has an efficiency factor of E=0,85 and the worst efficiency team has an efficiency factor of E=0,48. Which is our Efficiency Score?

FSS 2020
#172single-choiceverified

Your team has calculated from your vehicle model simulations that the minimum required battery pack energy to finish the Endurance is 6,5 kWh. Unfortunately, this year regenerative braking from electric motors will not be used during Endurance. Which of the following battery packages provides enough energy to finish the Endurance and also fulfils all requirements set in rule EV 5.3.2? Note 1: when calculating the total energy of the battery package use the nominal battery cell voltage. Note 2: when calculating the energy of the battery segment to verify rule EV 5.3.2 use the indicated battery cell voltage specified in the rules. Note 3: when calculating the segment mass, assume all mass is caused by the battery cells.

FSS 2020
#176single-choiceverified

A very simplified model for a brushless DC surface permanent magnet motor is presented in the figure. Its equivalent magnetic circuit has also been included. Calculate the flux density (Bg) in the airgap, assuming the cross-sectional area of the airgap is the same cross-sectional area as for the ferromagnetic material and the permanent magnet (1cmx1cm). The length of the two ferromagnetic material sections (Lc1, Lc2) and the airgap length (g) are presented in the figure. Also, the permeability of the ferromagnetic material is presented (μ) and assume the permeability of the airgap is the permeability of free space (μ0). The reluctance of the permanent magnet (Rm) and its remanent flux (Φr) are also provided. When you have calculated the airgap flux density (Bg) use the equation provided below to calculate an estimation of the electromagnetic motor torque (Τ) using the parameters in the table and the calculated airgap flux density value (Bg). Τ=2Nm NBg Lst Rro I where Nm represents the number of magnets, N represents the number of conductors per stator slot, Bg represents the airgap flux density, Lst is the stator motor length, Rro is the airgap radius and I is the stator DC phase current. Number of magnets: 4 Number of conductors per stator slot: 14 Stator motor length: 124 mm Airgap radius: 60 mm Stator DC phase current: 300 A

FSS 2020
#180input-rangeverified

Calculate the Normal Force on the rear left tire during the first Skidpad lap. You can assume, that your vehicle is in a steady-state condition and that there is no longitudinal acceleration. Furher it can be assumed, that all 4 wheels have a lateral grip coefficient of 1,4. You can use the cenerline radius stated in the rules. Following information regarding the vehicle are given: (answer in N) m=220kg, cl= 3.8, A=1m², p=1.1kg/m³, Wheelbase: L=1.53m, trackwidth: t=1.2m, Height of CG: h=0.2m weight distribution/COP: 50% Hint: R=9.125m Please use the following format: 12.3 or 1.23 (no ',' comma, no latters), round to 3 significant digits.

FSCH 2021FSCH 2024FSPT 2024