## Torque Required to Move a Car

The amount of torque required to move a car depends on a number of factors, including:

The weight of the car

The rolling resistance of the tires

The aerodynamic drag

The grade of the road

The transmission efficiency

### Weight of the Car

The weight of the car is the most significant factor in determining the amount of torque required to move it. A heavier car requires more torque to accelerate than a lighter car.

### Rolling Resistance

Rolling resistance is the force that opposes the motion of a tire rolling on a surface. It is caused by the deformation of the tire and the interaction between the tire and the surface. Rolling resistance increases with the weight of the car and the roughness of the surface.

### Aerodynamic Drag

Aerodynamic drag is the force that opposes the motion of a car through the air. It is caused by the shape of the car and the speed at which it is traveling. Aerodynamic drag increases with the speed of the car and the size of the car.

### Grade of the Road

The grade of the road is the angle of inclination of the road. A car requires more torque to climb a hill than to travel on a level road.

### Transmission Efficiency

The transmission efficiency is the ratio of the torque output by the transmission to the torque input by the engine. A transmission with a higher efficiency will require less torque from the engine to move the car.

### Calculating the Required Torque

The following equation can be used to calculate the torque required to move a car:

“`

T = (F r) / e

“`

where:

T is the torque required (in newton-meters)

F is the force required to move the car (in newtons)

r is the radius of the tire (in meters)

e is the transmission efficiency

### Example

Let’s say we have a car that weighs 1,500 kg, has a rolling resistance of 0.01, and is traveling at a speed of 60 mph on a level road. The car has a transmission with an efficiency of 90%.

The force required to move the car is:

“`

F = m g (1 + r)

“`

where:

m is the mass of the car (in kilograms)

g is the acceleration due to gravity (9.8 m/s^2)

r is the rolling resistance

“`

F = 1,500 kg 9.8 m/s^2 (1 + 0.01) = 14,700 N

“`

The radius of the tire is:

“`

r = (d / 2)

“`

where:

d is the diameter of the tire (in meters)

“`

r = (0.6 m / 2) = 0.3 m

“`

The torque required to move the car is:

“`

T = (F r) / e

“`

“`

T = (14,700 N 0.3 m) / 0.9 = 5,211 Nm

“`

Therefore, the car requires 5,211 Nm of torque to move at a speed of 60 mph on a level road.

### Tips for Improving Torque

There are a number of ways to improve the torque of a car, including:

Increasing the engine displacement

Using a turbocharger or supercharger

Installing a performance exhaust system

Upgrading the transmission

Reducing the weight of the car

By following these tips, you can improve the torque of your car and make it more fun to drive.

### Additional Information

The torque of a car is measured in newton-meters (Nm).

The horsepower of a car is a measure of the power output of the engine.

The torque and horsepower of a car are related by the following equation:

“`

P = T w

“`

where:

P is the horsepower

T is the torque (in newton-meters)

w is the angular velocity (in radians per second)

The torque of a car is most important at low speeds.

The horsepower of a car is most important at high speeds.