Physics Assignment on Laws of Motion. pptx

This is a presentation on Newtons laws of motion.

1. Laws of Motion Project: Physics Submitted by: Nidhish Class: 11 A Enrollment Number: 20210159394

2. Newton’s three laws of motion In the first law, an object will not change its motion unless a force acts on it. In the second law, the force on an object is equal to its mass times its acceleration . In the third law, when two objects interact, they apply forces to each other of equal magnitude and opposite direction.

3. What is Inertia? The first law is also known as the Law of Inertia. Law of inertia is the most important and renowned one. Inertia is defined as a property of matter by which it remains at the state of rest or in uniform motion in the same straight line unless acted upon by some external force . What are the types of inertia? There are three types of inertia: Inertia of Rest Inertia of Direction Inertia of Motion

4. Write examples to prove the law of inertia. The tendency of moving back when the stationary bus starts to move. Moving forward when a sudden brake is applied. Dust coming out of mat when beaten. Falling forward in transport when sudden breaks are applied. Leaves get detached from the tree when shaken hardly. Due to inertia, artificial satellites keep moving in a circular motion.

5. Equilibrium with examples The word equilibrium means ‘balance’ which indicates that a chemical reaction represents a balance between the reactants and products taking part in the reaction . An equilibrium represents a state in a process when the observable properties such as color, temperature, pressure, concentration etc do not show any change . pH formula of equilibrium is -log [H 3 O + ]. In the case of physical processes such as the melting of solid, dissolution of salt in water, the equilibrium is called  physical equilibrium The equilibrium associated with chemical reaction is known as a  chemical equilibrium .

6. Why is equilibrium important in chemistry? When the quantities of reactants and products are stable – their ratio does not change a chemical reaction is in equilibrium. This suggests that the reaction has reached a point where the reactant and product amounts remain constant over time, since the forward and backward reactions are at the same rate. There is no net change in concentrations of reactants and products. This kind of equilibrium is also called dynamic equilibrium.

7. Acceleration Newton's second law states that the acceleration of an object depends upon two variables – the net force acting on the object and the mass of the object. The acceleration of the body is directly proportional to the net force acting on the body and inversely proportional to the mass of the body.

8. What happens when multiple forces act on a object? Each force acts on one particular object and has both a strength and a direction. An object at rest typically has multiple forces acting on it, but they add to give zero net force on the object . Forces that do not sum to zero can cause changes in the object's speed or direction of motion.

9. What happens when one force acts on a body? A net force on an object changes its motion – the greater the net force, the greater the acceleration. More massive objects require bigger net forces to accelerate the same amount as less massive objects . Newton's second law of motion, force is equal to mass into acceleration, f = m × a , When the mass is constant, force is directly proportional to acceleration.

10. Conservation of Momentum The law of conservation of momentum states that in an isolated system the total momentum of two or more bodies acting upon each other remains constant unless an external force is applied. Therefore, momentum can neither be created nor destroyed . The law of conservation of momentum is based on Newton’s third law of motion which states that every force has a reciprocating equal and opposite force.

11. Formula of Conservation of Momentum The momentum observation principle can be represented as: m 1 u 1  + m 2 u 2  = m 1 v 1  + m 2 v 2 In the equation, m 1  and m 2  are masses of the bodies, u 1  and u 2  are the initial velocities of the body. v 1  and v 2  are the final velocities of the bodies . The thrust that you feel at the time of firing is one of the real-life examples of the conservation of momentum.

12. Following are the examples of law of conservation of momentum: Air-filled balloons . System of gun and bullet . Motion of rockets

13. Examples of Newton’s First Law One's body movement to the side when a car makes a sharp turn. Tightening of seat belts in a car when it stops quickly. A ball rolling down a hill will continue to roll unless friction or another force stops it. If pulled quickly, a tablecloth can be removed from underneath of dishes.

14. Examples of Newton’s Second Law We always see the applications of Newton's second law of motion in daily life when: Pushing a car and a truck Rocket launch Kick the ball Car crash

15. Examples of Newton’s Second Law Firing of a bullet A book lying on a table During swimming Rowboat moving through the water

16. Some questions with their answers Question 1. Explain why a cricketer moves his hands backwards while holding a catch. Answer: A cricketer moves his hand to increase the impact of the ball that is shot by the batsman, so that the force of the ball gets reduced to a comfortable limit without causing injury to the hands . Question 2.  If the mass of a bus is 2000 kg, what will the force required to speed up a bus at the 6ms –2 ? Answer: Acceleration (a) = 6m/s 2  and Mass (m) = 2000 kg, Force (F) =? F = m x a (Formula) = 2000 kg x 6m/s 2 = 12000 kg m/s 2 Therefore , required Force = 12000 N

17. Some questions with their answers Question 3. A car moving with a speed of 120Km/h along a straight highway and is brought to rest within a distance of 150m. How long does it take for the car to stop? Also, calculate the retardation of the car. Answer: Velocity of car v=120 km/h = 33.33 m/s Displacement s = 150 m Final velocity v = 0 m/s Applying second equation of motion to calculate retardation v 2 −u 2  = 2as =0 – (33.33)2 = 2(a) (150) = 3.70 m/s 2 Now, by applying the first equation of motion to calculate time t v= u+at (33.33) + (-3.70) t = 9.00 sec Hence, retardation is 3.70 m/s 2 , and the time take to stop is 9.00 sec.

18. Some questions with their answers Question 4. Why does a swimmer push the water backwards? Answer:  From the Newton's 3rd law of motion, we know that "when one body exerts a force on the other body, the first body experiences a force equivalent in magnitude in the opposite direction of the force exerted". As a result, in order to swim ahead, the swimmer pushes water backward with his hands.

19. Some questions with their answers Question 5. Explain why passengers are thrown forward form their seats when a speeding bus stops suddenly. Answer:  When a fast bus comes to a complete stop, the bottom half of the body in touch with the seat comes to a complete halt, while the upper section of the passengers' bodies prefer to retain their uniform motion. As a result, the passengers are pushed forward.

20. Thankyou!