Science Part 1
science maharashtra board 10th
- e. A ball falls off a table and reaches the ground in 1 s. Assuming g = 10 m/s2 , calculate its speed Given: t=2s , g=10 m/s² , u=0 , a=g , s=? , v=? Solution : s=ut+1/2 gt² = 0× 1+ 1/2 (10)(1)² = 1/2 (10) s= 5m v=u+gt =0+10*1 v=10 m/s The an... 1
- d. An object thrown vertically upwards reaches a height of 500 m. What was its initial velocity? the final velocity is zero. We know the position is 500 and acceleration is 10 Let the initial velocity = u final velocity = v v= 0 m/s s =... 1
- c. The mass and weight of an object on earth are 5 kg and 49 N respectively. What will be their values on the moon? Mass of the substance remains constant. It is the multiplication of density and volume that will remain unchanged in the whole universe. So... 2
- b. The radius of planet A is half the radius of planet B. If the mass of A is MA, what must be g= GMover R² ⇒ M=gR²/G Acording to the given data , gB/gA=1/2 and tfracR_BR_A=2 ⇒ M_B/M_A=g_B/g_A( R_B/R_A)² ⇒ M_B/M_A=1/22² ⇒ M_B=2M_A Vide... 1
- a. An object takes 5 s to reach the ground from a height of 5 m on a planet. What is the value of g on the planet? Given : Time= 5s , Height=5m To find : Gravitational acceleration Formula: S=ut+1/2gt² steps: by formula 5=0× t+1/2g(5)² 5=1/2g×25 therefore... 1
- 4. Let the period of revolution of a planet at a distance R from a star be T. Prove that if it was at a distance of 2R from the star, Thus, when the period of revolution of the planet at a distance R from a star is T, then from kepler's third law of planetry motion, we have... 1
- 3. Explain why the value of g is zero at the centre of the earth. Acceleration due to the earth's gravity is zero at the centre of the Earth because at that point the mass of the earth is equally distribute... 1
- e. If the value of g suddenly becomes twice its value, it will become two times more difficult to pull a heavy object along the floor. Why? Let the mass of the heavy object be m. Thus, the weight of the object or the pull of the floor on the object is W=mg Now, if g becomes twice... 2
- d. A stone thrown vertically upwards with initial velocity u reaches a height ‘h’ before coming down. Let us consider an object which is projected vertically upwards with initial velocity u which reaches a maximum height h. Acceleration due t... 1
- c. Write the three laws given by Kepler. How did they help Newton to arrive at the inverse square law of gravity? Kepler's first law: The orbit of a planet is an ellipse with the Sun at one of the foci. Kepler's Second law: The line joining the planet an... 2
- b What are (i) free fall, (ii) acceleration due to gravity (iii) escape velocity (iv) centripetal force ? (i) Free Fall: Whenever an object moves under the influence of the force of gravity alone, it is said to be in Free Fall. During free fall i... 1
- a. What is the difference between mass and weight of an object. Mass is the amount of matter present in an organism while weight of an object is mass along with gravitational force I. e. W=Mg. Mass of an... 1
- 1. study the entries in the following table and rewrite them putting the corrected items in a single row Answer: 123 MasskgMeasure of inertia WeightNZero at the centre (of the earth) Acceleration due to gravitym/s²Depends on height Gravitational... 1
- Refractive index of water with respect to air is 1.33 and that of diamond is 2.42. Refractive index = speed of light in vacuum/speed of light in medium Since the refractive index of diamond is more, hence the speed of light... 1