examples of force of friction
Answers
Answer:
We see friction in our day to day activities. Following are the ten examples of friction in daily life:
Walking –We can walk only if we apply frictional force. Friction is what holds your shoe to the ground. The friction present on the ice is very little, this is the reason why it is hard to walk on the slippery surface of the ice.
Writing – A frictional force is created when the tip of the pen comes in contact with the surface of the paper. Rolling friction is what comes into play while writing with a ballpoint pen while sliding friction arises when one writes with a pencil.
Skating – A thin film of water under the blade is necessary to make the skate slide. The heat generated by the skate blade rubbing against the surface of ice causes some of the ice to melt right below the blade where the skater glides over the ice. This water acts as a lubricant reducing friction.
Lighting a matchstick – When the head of the matchstick is rubbed against a rough surface, heat is generated and this heat converts red phosphorous to white phosphorous. White phosphorous is highly inflammable and the match stick ignites. Sometimes, matchsticks fail to ignite due to the presence of water. Water lowers friction.
Driving of the vehicle on a surface- While driving a vehicle, the engine generates a force on the driving wheels. This force initiates the vehicle to move forwards. Friction is the force that opposes the tyre rubber from sliding on the road surface. This friction avoids skidding of vehicles.
Applications of breaks in the vehicle to stop it- Friction braking is the most widely used braking method in vehicles. This process involves the conversion of kinetic energy to thermal energy by applying friction to the moving parts of a vehicle. The friction force resists the motion and in turn, generates heat. This conversion of energy eventually bringing the velocity to zero.
Flight of aeroplanes- Drag is the force that opposes the forward motion of the aeroplane. The friction which resists the motion of an object moving through a fluid or immobile in a moving fluid, as occurs when we fly a kite. The friction of the air is created as it meets and passes over an aeroplane and its components. Drag is generated by air impact force, skin friction, and displacement of the air.
Drilling a nail into the wall- Friction is responsible for fixing of nails in a wall. As the nail is driven into the wall, the nearby material to the nail of the wall gets compressed. This exerts a force on the nail. This force is the friction that converts the normal force exerted by the compressed layers of the wall into the resisting shear force. In this manner the friction cause nails and screws to hold on to walls.
The dusting of the carpet by beating it with a stick- When the carpet is beaten with the stick, the dust comes out. The dust is carried off by the wind or falls on the floor. The carpet exhibits a little static friction that holds the dust to the carpet. When the carpet is beaten, it will overcome the friction and the carpet will move away from the dust making the carpet free from dust.
Sliding on a garden slide- We know that friction is a force that is present whenever two objects rub against each other. In case of a slide in the garden such as a slide and a person’s backside rub each other’s surface. Without friction, a slide would accelerate the rider too quickly, resulting in possible injury due to the fall. The friction reduces the velocity of the sliding person and makes him stop.
Friction is seen everywhere other than these areas in day to day life. Rubbing hands, table drawer are other examples of friction.
Answer:
Frictional force refers to the force generated by two surfaces that contacts and slide against each other.
A few factors affecting the frictional force:
These forces are mainly affected by the surface texture and amount of force impelling them together.
The angle and position of the object affect the amount of frictional force.
If an object is placed flat against an object, then the frictional force will be equal to the weight of the object.
If an object is pushed against the surface, then the frictional force will be increased and becomes more than the weight of the object.
Explanation:
The maximum amount of friction force that a surface can apply upon an object can be easily calculated with the use of the given formula:
Ffrict = µ • Fnorm
To help you calculate the frictional force, here we have provided methodical steps to follow while calculating the force of friction.
Find the Normal Force
The normal force is the support force exerted upon an object that is in contact with another stable object. The normal force can be simply described in most cases by the following formula:
N = mg
In this formula, m describes the mass of the object, and g stands for the acceleration due to gravity. In case of an inclined surface, the strength of the normal surface is reduced the more the surface is inclined, hence the formula becomes:
N = mg cos(θ)
θ represents the angle the surface is inclined to. In a simple calculation, you would calculate the normal force of a 2-kg block of wood sitting on a surface as N = 2 kg × 9.8 N/kg = 19.6 N
Finding the Right Co-efficient
The co-efficient that you would choose depends on the object and the specific situation. If the object isn’t moving across the surface, you use the coefficient of static frictionμstatic, but if the object under consideration is moving you use the coefficient of sliding friction μslide. The type of materials used also affects the co-efficient. For example, if a block wood was on a brick surface, the coefficient would be 0.6, but if it were on a block of clean wood, it would range from 0.25 to 0.5.
Calculating Frictional Force
As discussed, the formula for frictional force is given by F = μN.
As an example, let us consider the block of wood that weighs 2-kg resting on a table to be pushed from rest. In this case, we consider the static friction co-efficient. 0.5 is the static co-efficient of wood.
With the given details, we can calculate the normal force as N = 2 kg × 9.8 N/kg = 19.6 N Now that we have the values of normal force and static friction co-efficient, we can calculate the frictional force as follows:
F = 0.5 × 19.6 N = 9.8 N
Example -
Problems on Frictional Force
1. A large block of ice is being pulled across a frozen lake. The block of ice has a mass of 300 kg. The coefficient of friction between two ice surfaces is small: μk = 0.05. What is the force of friction that is acting on the block of ice?
Solution: On a flat surface, the normal force on an object is given by N = mg.
With this, we can find the force of friction as follows:
Ff =μN
Ff =μmg
Substituting the values in the above equation we get,
Ff =0.05 × 300 kg × 9.8 m/s2
= 147 kg-m/s2 or 147 N.
The force of friction acting in the opposite direction as the block of ice is pulled across the lake is 147 N.
2. A man has to push his boat on the shore across the mud to get to the water. The coefficient of friction between the boat and the mud is given by μ = 0.400. If the boat has a mass of 40 kg, calculate the magnitude of the force of friction acting on the boat.
Solution: On a flat surface, the normal force on an object is N = mg.
Using this, we can calculate the force of friction as follows:
F = μN F = μ mg Substituting the values in the equation, we get F = (0.400)(40.0 kg)(9.80 m/s2)
F = 156.8 N
The frictional force acting on the boat is 156.8 N.