## What is difference between rotation and rolling?

Rotational motion means that your body moves around a fixed axis, for exapmle consider the rotation of the Earth. Rolling is a special kind of motion, when a body is rotating around a moving axis. The axis is translating, while the body is rotating around it.

**How is rolling power calculated?**

The ratio λ = [ a/Lp] = [a/√R. ∆t] is used to calculate the moment arm ‘a’ λ =0.5 for hot rolling and 0.45 for cold rolling. Where P=Load in Newton, a=moment arm in meters and N=speed rollers This gives the power required for deformation of metal only.

**What do you mean by rolling motion?**

Rolling is a type of motion that combines rotation (commonly, of an axially symmetric object) and translation of that object with respect to a surface (either one or the other moves), such that, if ideal conditions exist, the two are in contact with each other without sliding.

### What causes rolling?

A wheel will start rolling when a force is applied and there is a resistive force or friction at the point of contact with the ground. The force may be a torque or a linear push on the wheel. Static friction causes the rolling motion. It is also called the traction of the wheel.

**Is pure rolling practically possible?**

Now in this case if surface is frictionless, there would not be any torque/ force which can bring the velocity (v) equal to w x r and pure rolling will not occur. We can say pure rolling can occur without friction depending upon how you have started.

**What are the conditions for pure rolling?**

It must accelerate or decelerate respectively. A disc is rolling on a rough horizontal surface. The instantaneous speed of the point of contact during perfect rolling is zero with respect to ground. The force of friction can help in achieving pure rolling condition.

#### How do you find rolling torque?

The torque is obtained by integrating the frictional force multiplied by roll radius over the arc of contact (lagging and leading zones). The negative sign before the second term is due to the fact that in leading zone the metal moves faster than the rolls hence it helps to rotate the rolls.

**What is angle of bite in rolling?**

In rolling metals where all forces are transmitted through the rolls, the maximum angle that can be attained between the roll radius at the first contact and the line of roll centers. Operating angles less than the angle of bite are called contact or rolling angles.

**Is rolling faster than sliding?**

Since the sliding object has no angular velocity, its linear velocity is greater than that of the rolling object, and it reaches the bottom of the track faster.

## Is there no friction in pure rolling?

Frictional force is not zero in a rolling motion An object is able to roll only because friction prevents the bottom part from slipping. Else the body would simply slip through the floor.

**Why does a wheel stop rolling?**

The friction force causes angular acceleration of the wheel. The wheel stops slipping when the point in contact with the ground is not moving relative to the ground. That means the angular velocity and linear velocity of the wheel must be related by v=rω where r is the radius of the wheel.

**Is friction always necessary for rolling?**

So friction is necessary for a ball to start rolling but once the rolling condition has been met the ball experiences no friction. If the wheel is rolling at constant velocity without any other forces acting, then there is no tendency for slippage between the wheel and the surface, so there is no friction.

### What is rolling, torque, and angular momentum?

Rolling, Torque, and Angular Momentum Rolling Motion: • A motion that is a combination of rotational and translational motion, e.g. a wheel rolling down the road. • Will only consider rolling with out slipping.

**How is torque related to the axis of rotation?**

Torque is the measure of the force that can cause an object to rotate about an axis. Force is what causes an object to accelerate in linear kinematics, similarly, torque is what causes an angular acceleration. Hence torque can be defined as the rotational equivalent of linear force. The point where the object rotates is called the axis of rotation.

**How is the torque of a car calculated?**

The value of λ has been calculated by Sim by calculating torque by Eqn. (7.71b) for a large range of rolling conditions. For hot rolling λ varies between 0.49 to 0.45. Lower values are for higher reductions. For cold rolling, the value of λ varies from 0.36 to 0.45.

#### Which is the best definition of the word torque?

Torque is the expression of a rotational or twisting force. The engines in vehicles rotate about an axis, thus creating torque. It can be viewed as the strength of a vehicle. Torque is what rockets a sports car from 0-60 in seconds. Torque is also what powers big trucks hauling heavy loads into motion.

Rolling, Torque, and Angular Momentum Rolling Motion: • A motion that is a combination of rotational and translational motion, e.g. a wheel rolling down the road. • Will only consider rolling with out slipping.

The value of λ has been calculated by Sim by calculating torque by Eqn. (7.71b) for a large range of rolling conditions. For hot rolling λ varies between 0.49 to 0.45. Lower values are for higher reductions. For cold rolling, the value of λ varies from 0.36 to 0.45.

**How is rolling motion a combination of rotation and translation?**

Rolling motion is a combination of pure rotation and pure translation. Each velocity vector on the wheel is a sum of~v comand the rotation. Chapter 11 – Rolling, Torque, and Angular Momentum Rolling Angular Momentum Conservation of Angular Momentum Rolling Rolling motion is a combination of pure rotation and pure translation.

**How is the torque of a cold rolled sheet determined?**

The relationship between T r -the torque required at the rolls and T rm (which is T r converted to motor shaft) is the gear ratio (G r) between motor shaft and the roll as illustrated below- A 1000 mm wide and 2mm thick mild steel sheet is cold rolled to 1.5 mm thickness.