9th
9th board exam books question should be asked in this category for easy navigation if found other question please report or comment it
- Prove that the kinetic energy of a freely falling object on reaching the ground is nothing but the transformation Answer: At height h the object has potential energy mgh and zero kinetic energy; on reaching the ground its kinetic energy is also mgh, so a... 1
- Derive the formula for the kinetic energy of an object of mass m, moving with velocity v. Kinetic energy is the energy possessed by an object by virtue of its motion. K.E=1/2 mV² Derivation: Let us consider an object of m which is... 1
- Explain the difference between potential energy and kinetic energy. Kinetic Energy Potential Energy (i) Kinetic energy is the energy possessed by the body due to its motion. (i) Potential energy is the energy... 1
- Does the angle of banking depend on the mass of the vehicle? It does not depends upon mass of the vehicle as it only depends upon:- 1.acceleration due to gravity 2.radius of curvature 3.speed of the ve... 1
- A person swims 100 m in the first 40 s, 80 m in the next 40 s and 45 m in the last 20 s. What is the average speed? formula for velocity is given as; v=x/t therefore, v₁=x₁/t₁=100m/40sec=2.5m/s. v₂=x₂/t₂=80m/40sec=2m/s v₃=x₃/t₃=45m/20sec=2.25m/s Vavg=V1+V2... 2
- A bullet having a mass of 10 g and moving with a speed of 1.5 m/s, penetrates a thick wooden plank of mass 90 g. Answer: 0.15 m/s Use the law of conservation of momentum: total momentum before = total momentum after. Convert masses to kg: bullet m₁ = 10... 1
- An object of mass 16 kg is moving with an acceleration of 3 m/s2 . Calculate the applied force. Answer: Force = 48 N; acceleration of the 24 kg object = 2 m/s² By Newton's second law, F = ma . For the 16 kg object: F = 16\ kg × 3\ m/s²... 1
- An object moves 18 m in the first 3 s, 22 m in the next 3 s and 14 m in the last 3 s. What is its average speed? Average speed = Total \ Distance/Total \ time = 18+22+14/3+3+3=54/9 =6m/s 1
- Take 5 examples from your surroundings and give explanation based on Newtons laws of motion. 1) When a ball is kicked in space, the ball keeps moving in one direction as there is no gravity. The ball stops when it hits an object or p... 2
- Give scientific reasons. d. The velocity of an object at rest is considered to be uniform. Velocity of an object is said to be uniform when its speed and direction does not change. The object at rest has uniform speed of zero all t... 1
- Give scientific reasons. c. It is easier to stop a tennis ball as compared to a cricket ball, when both are travelling Momentum of a body is the product of its mass and velocity i.e. p=mv and the rate of change of momentum of a body is equal to the force appl... 1
- Give scientific reasons. b. Even though the magnitudes of action force and reaction force are equal and their When two bodies interact, the action and reaction forces come into action. Even though their magnitude are same and their direction are oppo... 1
- Give scientific reasons. a. When an object falls freely to the ground, its acceleration is uniform. When an object falls freely to the ground, it is under the effect of a constant force known as force of gravity. No other forces act on it.... 1
- Complete the sentences and explain them. Laws of motion a. The minimum distance between the start and finish points of the motion of an object is called the displacement of the object. => The shor... 1
- Complete the following table. u (m/s) a (m/s2) t (sec) v = u + at (m/s) 2 u (m/s) a (m/s²) t (sec) v = u + at (m/s) 2 4 3 14 10 5 2 20 u (m/s) a (m/s²) t (sec) s=ut + 1/2at² (m) 5 12 3 69 7 8 4 92 u (m/s) a (m/s²)... 1
- Clarify the differences Uniform and non-uniform motion. Uniform motion Non-uniform motion When an object covers equal distance in equal time interval, it is said to be in uniform motion. When an o... 1
- Clarify the differences Distance and displacement Distance Displacement It is defined as the length of the actual path travelled by an object in motion. It is defined as the shortest distanc... 1
- Match the first column with appropriate entries in the second and third columns and remake the table. S.no Column 1 Column 2 Column 3 1 Negative acceleration the velocity of object decreases A vehicle moving with the velocity of 10 m/s, stops... 1
- Why can an X-ray telescope not be based on the earth? X-rays are emitted from distant heavenly bodies. The rays coming towards the earth will be absorbed by the earth’s atmosphere and will go un... 1
- Why are optical telescopes located in uninhabited places on mountains? Optical telescopes situated on the surface of Earth, does not produce images of good quality of the following reasons: Intensity of light ra... 1
- Explain the construction of a radio telescope. These telescopes are used to see radio waves coming from space. It has one or more dishes of parabolic shape. The rays coming from the dista... 1
- Explain the construction of Galileo’s telescope. The Galileo’s telescope is made up of two or more convex lenses. The lens facing the object is called the objective lens which is made as la... 1
- Study the figure and answer the following questions What type of telescope is shown in the figure? a. Newtonian telescope is shown in the given figure. b. c. Both plane and spherical mirror is used in this telescope. The spherical mirror i... 1
- Which type of telescopes can be made using a concave mirror, convex mirror, plane mirror and a lens? Reflecting types of telescopes can be made using a concave mirror, convex mirror, plane mirror and a lens. Reflecting type of telescopes is... 1