# Aerodynamics Questions and Answers – Energy Equation

This set of Aerodynamics Multiple Choice Questions & Answers (MCQs) focuses on “Energy Equation”.

**1. A body moves 5m in a forward direction and then comes back to the same position. Which of the following energy does it have?**

a) Potential energy

b) Sum of kinetic energy plus potential energy

**c) Kinetic energy**

d) Impulsive energy

**Explanation:** Kinetic energy is always present in a moving item. When a body moves ahead, it gains kinetic energy, which is calculated as the product of mass and velocity squared. Kinetic energy is always stored in a moving body.

**2. The SI unit of kinetic energy is ___________**

a) Newton

**b) Joules**

c) Pascal

d) Meters

**Explanation:** Kinetic energy is calculated using the formula 0.5*m*v2. The dimensional formula for kinetic energy is kg*(m/s)2, where 1 joule is defined. kg*m2/s2 = 1 joule The energy supplied to an object when a force of 1 Newton is applied to a body over a distance of 1 metre is defined as 1 Joule.

**3. Determine the kinetic energy of the body of mass 90 kg moving with a speed of 200 m/s.**

a) 15000 Joules

**b) 900000 Joules**

c) 21000 Joules

d) 40000 Joules

**Explanation:** KE=0.5*m*v^{2}.

Substitute the values in the formula.

Here, m=90 kg and v= 200 m/s.

On solving the above equation we get,

KE=0.5*90*(200)^{2}= 900000 Joules.

**4. The energy equation, the total energy is equal to the sum of _______**

a) Kinetic energy + potential energy

b) Kinetic energy + pressure energy

**c) Kinetic energy + potential energy + pressure energy**

d) Pressure energy + potential energy

**Explanation:** The sum of kinetic energy, potential energy, and internal energy is the total energy. Where kinetic energy is calculated using the formula 0.5 m*v2, where m is mass and v is velocity. PE=mgh is the formula for potential energy, where m is the mass, g is the gravitational acceleration, and h is the height. The letter ‘I’ stands for internal energy.

**5. In a thermodynamic system, the measurement of heat is called as ___________**

a) Entropy

**b) Enthalpy**

c) Internal energy

d) Heat transfer

**Explanation:** The overall heat content of a system is measured as enthalpy. It is a broad attribute that includes internal energy as well as the product of pressure and volume.

H = U+ p*V

**6. The enthalpy is _____**

**a) H = U+ p*V**

b) H = U+ p

c) H = U+I

d) H = U+ p*V^{2}

**Explanation:** The overall heat content of a system is called enthalpy. The letters ‘H’ stand for enthalpy, ‘U’ for internal energy, ‘p’ for pressure, and ‘V’ for volume. The term “enthalpy” refers to a wide range of properties. The product of internal energy plus the product of pressure and volume equals it.

**7. Conservation of energy is based on which law of thermodynamics?**

**a) First law of thermodynamics**

b) Second law of thermodynamics

c) Zeroth law of thermodynamics

d) Third law of thermodynamics

**Explanation:** Energy cannot be generated or destroyed, according to the first law of thermodynamics, but it can be changed from one form to another.

**8. The kinetic energy of an object depends only on magnitude.**

a) True

**b) False**

**Explanation:** The magnitude of kinetic energy is all that matters. The product of mass and velocity squared is kinetic energy. Because the dot product of a vector quantity is always scalar, it is a scalar quantity that is solely affected by magnitude.

**9. The formula for kinetic energy is __________**

a) KE = 0.5*m*v

**b) KE = 0.5*m*v ^{2}**

c) KE = m*v

^{2}

d) KE = 0.6*m*v

^{2}

**Explanation**: It is the product of mass and velocity squared. Kinetic energy is relevant in the case of moving things as well as those with a specific mass. It is defined as the effort required to move a body from a resting to a moving state.

The first law of thermodynamics, sometimes known as the law of conservation of energy, is expressed by the energy equation. To begin, write a balance equation for the rate of change of kinetic and internal energy. The specific heat at constant volume can be connected to the internal energy, U. (cv). Kinetic energy is always present in a moving item. When a body moves ahead, it gains kinetic energy, which is calculated as the product of mass and velocity squared. Kinetic energy is always stored in a moving body.