Questions

This problem solves a standard vapour compression refrigeration cycle using R134a refrigerant, with evaporator temp -5°C and condenser temp 35°C. Learn to calculate refrigeration effect per kg, isentropic compressor work, and coefficient of performance using refrigerant property tables.

This undergraduate thermodynamics problem calculates refrigeration effect, compressor work, and COP for a VCR system with R134a, operating at 0°C evaporator and 40°C condenser temperatures with isentropic compression.

This university-level thermodynamics problem solves for mass flow rate, compressor power, and COP of an R22 VCR system delivering 10 kW cooling, with -10°C evaporator and 38°C condenser temperatures.

This problem asks to find the value of tan B as a simplified fraction in a right triangle DCB (right-angled at C) with given side lengths DC = √31 and CB = 12. The solution uses the definition of the tangent trigonometric ratio for acute angles in right triangles, identifies opposite and adjacent sides relative to angle B, and simplifies the resulting fraction.

This 9th grade math problem asks to find ∠PTS given PT=QT=QR, RT=RS, and ∠PTQ=36°. The solution uses properties of isosceles triangles, the triangle angle sum theorem, and supplementary angles to calculate the final angle as 90°.

This is a junior high school geometry problem asking to find the measure of ∠PTS given PT=QT=QR, RT=RS, and ∠PTQ=36°. It requires applying properties of isosceles triangles, the triangle angle sum theorem, supplementary angles, and vertical angles to calculate the unknown angle step-by-step.

This junior high school physics question asks to identify the correct definition of speed from four options. Test your knowledge of kinematic quantities, scalar vs vector measurements, and the foundational speed formula with this practice problem.

This is a junior high school geometry problem that requires calculating ∠PTS using properties of isosceles triangles, the triangle angle sum theorem, and supplementary angle relationships, given PT=QT=QR, RT=RS and ∠PTQ=36°.

Learn the step-by-step process to simplify the polynomial subtraction expression $(4x^{3}-2x^{2}+5x-1)-(x^{3}+3x^{2}-2x+4)$, including applying the distributive property, identifying like terms, and combining coefficients to get the final simplified form.

Learn how to solve the 8th-grade system of linear equations $\\begin{cases}2x + y = 8 \\\\ x - y = 1\\end{cases}$ using the elimination method, step-by-step solution, verification, and core knowledge points explained.

This is a set of basic division practice problems for Grade 3 primary school students, covering single-digit divisor calculations and using the inverse relationship between multiplication and division to solve them. The problems include 5÷5, 6÷3, 18÷2 and 28÷4, testing mastery of fundamental division rules and multiplication facts.

Learn how to evaluate the algebraic expression 3x² - 2xy + 4y² by substituting x=-3 and y=2, following order of operations and rules for signed numbers to get the correct result of 43.