# Vehicle Dynamics MCQ – Set 3

This set of Vehicle Dynamics Multiple Choice Questions & Answers (MCQs) focuses on “Basic Concepts of Acceleration Performance”.

1. What is the limiting factor for acceleration performance at low speeds?
a) Tire traction
b) Rolling resistance
c) Drag
d) Lift

Explanation: Tire traction generated between the tire and the road determines the acceleration of the vehicle at low speeds. There is sufficient engine power to maintain the low speed. Rolling resistance produces a braking effect and is a continual decelerating force at all speeds which is overcome by the engine power. Drag and lift forces produce significant resistance at high speeds.

2. Which of the following forces provides the most resistance to the engine while accelerating at high speeds?
a) Gravity
b) Internal friction in the driveline
c) Rolling resistance
d) Aerodynamic drag

Explanation: The aerodynamic drag forces are directly proportional to the square of the speed. Internal friction in the driveline, rolling resistance, and the road grade, all remain nearly constant at high speeds.

3. What is the acceleration of a Lamborghini Aventador?
a) 2.5 seconds from 0 km/h to 100 km/h
b) 2.9 seconds to 0 km/h to 100 km/h
c) Under 2.5 seconds 0 km/h to 100 km/h
d) 7.8 seconds to 0 km/h to 100 km/h

Explanation: Acceleration performance at high speeds depends on the power to weight ratio of the vehicle. Lamborghini Aventador, with a 700 hp engine power capacity and 1.5-ton weight can accelerate from 0 to 100 km/h in 2.9 seconds. 7.8 seconds from 0 to 100 km/h is common for passenger cars. F1 cars can accelerate to 100 km/h in 2.5 seconds or less.

4. Rolling resistance is a major resistive force at high speeds.
a) True
b) False

Explanation: Rolling resistance becomes constant at high speeds. Normally at high speeds, the aerodynamic drag is the major resistive force. Rolling resistance dominates among the other resistive forces in the low-speed range.

5. Generally, trucks have better acceleration than passenger cars at the same speed.
a) True
b) False

Explanation: Acceleration is inversely proportional to the forward speed and weight of the vehicle. It is directly proportional to the power of the engine. At the same speed, the power to weight ratio of trucks is lower than the passenger cars, hence trucks have lower acceleration than passenger cars.

6. Which axis is used to define forward acceleration in the Vehicle Fixed Coordinate System?
a) z-axis
b) y-axis
c) x-axis
d) perpendicular axis

Explanation: In the Vehicle Fixed Coordinate System, the x-axis represents the forward direction, the y-axis represents the lateral direction from the right of the vehicle and the z-axis represents the downward direction with respect to the vehicle. Therefore, the x-axis is used to define the forward acceleration.

7. Engine power is transmitted to the wheels through the _____
a) Transmission system
b) Braking system
c) Suspension system
d) Steering system

Explanation: The transmission system transmits the power from the engine to the wheels via the clutch, gearbox, propeller shaft, differential, and the driveshaft. The braking system is used for decelerating the car. The suspension system comprises of a spring and damper system which is essential to absorb shocks for a comfortable ride. The steering system is used to maneuver the car.

8. Which law governs linear acceleration analysis in vehicle dynamics?
a) Newton’s third law of motion
b) Newton’s first law of motion
c) Newton’s zeroth law of motion
d) Newton’s second law of motion

Explanation: Newton’s second law of motion or F = m.a, where ‘F’ is the vector summation of all the forces applied on a body, ‘m’ is the mass of the body and ‘a’ is the resultant acceleration produced, governs the linear acceleration analysis. Newton’s third law of motion, which is “Every action has an equal and opposite reaction.”, is used in crash analysis. Newton’s first law describes states that a body remains in its state of motion or rest until and unless acted upon by an external force.

9. Theoretically, maximum acceleration on a given road is given by _____ between road and tire times the acceleration due to gravity.
a) coefficient of acceleration
b) coefficient of restitution
c) coefficient of friction
d) coefficient of traction

Explanation: Maximum acceleration due to the tractive force that can be generated when a vehicle is in motion is given by the coefficient of friction between the road and tire times the acceleration due to gravity. This acceleration is limited by engine power and road loads. Coefficient of restitution is used to describe energy loss during a collision.

10. 1 bhp is equal to _____ watts.
a) 735.5
b) 745.7
c) 576.8
d) 132.8

Explanation: Brake horsepower or bhp or the imperial horsepower is equal to 745.7 watts. On the other hand, metric horsepower is equal to 735.5 watts.

Sanfoundry Global Education & Learning Series – Vehicle Dynamics.

To practice all areas of Vehicle Dynamics, here is complete set of Multiple Choice Questions and Answers.

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