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Explain law of conservation of momentum? Also drive its formula?
The momentum of an isolated system of two or more than two or more than two interacting bodies remain constant.
we can write it as, Total momentum of gun and bullet before fixing =0 let m be the mass of the bullet and v be its velocity on firing the gun; M be the mass of the gun and V is the Velocity with which it recoids. thus the total momentum of the gun is fired will be: The momentum of the gun and the bullet after the gun is fired = Mv+ mv Total momentum before firing = Total momentum after firing Mv =- mv or v=-m/M v
An isolated system is a group of interacting bodies on which no external force is acting
. IF no unbalanced on net force acts on a system then its momentum remains constant.
Consider a system of gun and a bullet. Before firing, the Velocity of the bullets as well as that of
gunwas zero. therefore the total momentum of both the objects was also zero.
When the gun is fired bullet shoots out of guns and acquire momentum
.To converse momentum the qunrecoils backward. Now according to the law of conversation of momentum, the total momentum of the gun and bullet will also be zero after the gun is fired.
According to the law of conversation of momentum.
Two masses 26 Kg and 24 kg<gwmw class="ginger-module-highlighter-mistake-type-3" id="gwmw-15856603890924975919179">are attached</gwmw>to the ends of<gwmw class="ginger-module-highlighter-mistake-type-3" id="gwmw-15856603890921330649628">string</gwmw>which passes over a frictionless pulley. 26 kg is<gwmw class="ginger-module-highlighter-mistake-type-3" id="gwmw-15856603896464221407055">laying</gwmw>over a smooth horizontal table. 24 N mass is
a= m1g/m1 +m2 a= 24x10/24+26 a =240/50 a =4.8ms-² a=4.8ms-²
m2 g/m1 +m2
T = 124.8N
T =125 N
State the Newton's first law of motion & Second law of motion.
Newton first law:
a x f _______>(1) a x 1/m _____> (2) a x F/m a = Constant x F/m a = k x F/m a = 1ms-² ,F= 1N then the value of k will be 1. So the equation can be written as a=1x F/m
A body continues in its state of rest or of uniform motion in a straight line provided no net force acts on it.
Explanation for rest:
Similarly Newton's first law of motion deals with bodies which are either at rest or moving with uniform speed in straight lineAccording to first law of motion, a body at rest remains at rest provided no net force on it
. thispart of the law is true as we observe that objects do not move by themselves unless some moves it.
Explanation for motion:
Similarly a moving object does not stop moving by itself. A ball rolled on a rough ground stops earlier than that rolled on smoothground. It is because
rough surface offer greater friction. If there would be no force of oppose the motion of the body would never stop
Newton's Second Law of Motion:
When a net force acts upon a body, it produces as acceleration
in the body in the direction of force and the magnitude of acceleration is directlyproportional to the net force and is inversely proportional to the mass of the body.
If the force f is acting on the body of mass m then we can write this in the mathematical form is as
From (1) and (2) we have
In the above equation according to the international system units if m= 1kg
A force of 20 N moves a body with an acceleration of 2ms-² What is the mass.
F = 20 N
a= 2ms-² m=? m = 10 kg
So m= 20/2
Explain Centripetal force and Drive F<sub>c</sub>= <gwmw class="ginger-module-highlighter-mistake-type-1" id="gwmw-15856633719363121477100">mv<sup>2</sup></gwmw>/<gwmw class="ginger-module-highlighter-mistake-type-1" id="gwmw-15856633908860274704462">r</gwmw>.<div></div>
A force that keeps a body
to move in a circle is known as centripetal force. Fc = ma, a ,=v²/r
Consider a body tied at the end of a string moving with uniform speed in a circular path. A body has the tendency to move in a straight line due to inertia. The string to which body is tied keeps it
to move in a circle by pulling the body towards the center of the circle. The sting pulls the center of the circle . the string pulls the body perpendicular to its motion. The pulling force continuously changesthe direction of motion and remains towards the center seeking force is called the centripetal force.
ma ,+ mv²/r
<gwmw class="ginger-module-highlighter-mistake-type-1" id="gwmw-15856688040949382175928">how</gwmw> much centripetal force is needed to make a body of mass 0.5 kg to move <gwmw class="ginger-module-highlighter-mistake-type-3" id="gwmw-15856688040946401839963">to</gwmw> a circle of radius 50cm with a speed 3 ms-¹
As we know that
Define dynamics, also briefly explain force , inertia and momentum<div><br></div>
Dynamics: the branch of mechanics that deals with the study of motion fo an object and cause of its motion is called dynamics
Explain Newtons first law of motion
Statement: A body continues its state of rest or of uniform motion in a straight line provided no net force acts on it.
Explain Newtons second law of motion
When a net force acts on a body, its produces acceleration in the body in the direction of the force. The magnitude of this acceleration is directly proportional to the net force acting on the body and inversely proportional to its mass
Write differences between mass and weight
Mass: Mass o a body is the quantity of matter possessed by the bodyits a scaler quantityit is measured by using a common balance( beam balance)it remains same everywherethe SI unit of mas is kilogram(kg)it is a base quantity
Write third law of motoin. explain it with examples
Statement: to every action there is always an equal but opposite reaction
Derive relation for tension and acceleration when two bodies moving along vertically
Consider two bodies A and B of masses m1 and m2 respectively. Let m1 is greater than m2. The bodies are attached to the opposite ends of an inextensible string. The string passes over a frictionless pulley. The body A being heavier must be moving downward with some acceleration. Let this acceleration be a. At the same time, the body B attached to the other end of the string moves up with the same acceleration a. As the pulley is frictionless, hence tension will be the same throughout the string. Let the tension in the string be T.
Derive tension and acceleration when one body move vertically and other body move horizontally
Consider two bodies A and B of masses m1 and m2 respectively attached to the ends of an inextensible string. Let the body A moves downward with an acceleration a. Since string is inextensible , therefore, body B also moves over the horizontal surface with the the same acceleration. As the pulley is frictionless, hence tension T will be the same throughout the string.
How you can relate a force with the change in momentum of a body
Consider a body of mass m moving with initial velocity vi. Let a force F acts on the body which produces an acceleration a in it. The changes the velocity of the body. Lets its final velocity after time t become vf. Ig pi and pf be the initial momentum and final momentum of the body related to initial and final velocities arepi=mvipf=mvfchange in momentum= final momentum- initial momentumpf-pi= mvf-mvi
Explain law of conservation of momentum
Statement: The momentum of an isolated system of two or more than two interacting bodies remains constant
Explain gun and bullet system using law of conservation of momentum
consider a gun and bullet system before firing the gun, both gun and bullet are at rest so the total momentum of system is zero.As the gun is fired bullet shoots out of the gun and acquires momentum. To conserve momentum of system the gun recoils. According to law of conservation of momentum, the total momentum of gun and bullet will also be zero after gun is fired . Let m be the mas of bullet and v be its velocity on firing the gun. M be the mass of gun and V be the velocity of gun with which it recoils'Total momentum of the gun and the bullet after the gun is fired = MV+mvaccording to law of conservation of momentumTotal momentum of gun and bullet after fire= Total momentum of gun and bullet before fireMV+mv=0MV=-mv
define and explain friction
Friction: the force that opposes the motion of moving objects is called frictionFactors: in case of solid, forces of friction between two surfaces depends upon many factors such as:nature of two surfaces in contactpressing force between them
Define rolling friction. Also explain why rolling friction is less than sliding friction
Rolling friction: force of friction between body and surface when a body rolls over a surface e.g. when a wheel rolls on ground
Explain braking and skidding
The wheels of moving vehicles have two velocity componentsmotion of wheels along the roadrotation of wheels about their axisto move a vehicle on the road as well as to stop a moving vehicle requires friction between its tyres and the road. For example, if the road is slippery or the tyre are worn out then the typre instead of rolling, slip over the road,The vehicle will not move if the wheels starts slipping at the same point on the slipper ty road. Thus for the wheels to roll, the force of friction9gripping force 0 between the tyres and the road must be enough that prevents them from slipping.if we want to stop a car quickly, a large force of friction between the tyres and the road is needed. But there is a limit to this force of friction that tyres can provide. If the breaks are applied too strongly, The wheels of th car will lock up ( stop turning) and the car will skid due to its large momentum. If we want t o reduce the skidding, it is necessary not to apply breaks too hard that lock up their rolling motion. It is unsafe to derive a vehicles wit worn out tyres .
Write the advantages and disadvantages of friction, also give methods to reduce friction
Advantage; sometimes friction is most desirablewe cannot write if there is no friction between paper and pencilfriction enables us to walk on road. We cannot run on a slippery ground because a slippery ground offers very little frictionbirds cannot fly if there is no air resistance
Define and explain centripetal force
Centripetal force: a force that keeps a body to move in a circular path is called centripetal force
Define centrifugal force and explain it briefly
Centrifugal force :A force that pulls outward the body moving in circular path us called centrifugal forceORThe reaction of centripetal force is known as centrifugal force
Write note on application of centripetal force
There are many application of centripetal force but some are following