Life_in_Plastic_Era

Satya Prakash Public School Session 2010-2011 Holiday Homework CLASS – X SUBJECT : SCIENCE ASSIGNMENT – CHAPTER 1 – LIFE PROCESSES Q1 From the given list identify the food reserves of plants and animals Glucose, Sucrose, Glycogen , Starch , Proteins , Fats Q2 Study the following diagram : [pic] Name the labeled part A & B and state their function Q3 Where do plants get each raw material required for photosynthesis ' Q4 Explain the process of photosynthesis . List four factors which influence this process and describe how each of them affects the rate of photosynthesis . Q5 Define Nutrition . List two differences between saprophytic and Holozoic nutrition. Q 6 Draw the diagram for cross section of a leaf and label the following – chloroplast, guard cell, lower epidermis, Upper epidermis. Q7 What happens to a plant if its leaves are coated with Vaseline' Q8 Why is it necessary to destarch a plant before performing an experiment to show photosynthesis ' Q9 Represent photosynthesis by means of a chemical equation . Also describe the three main events which help in carrying out photosynthesis . Q10 You are given a plant with variegated leaves. Which experiment will you perform to prove one of the requirements in photosynthesis . describe the experiment' Q11 Draw the diagram of human alimentary canal and label the following : a) the tube through which food passes into the stomach b) A structure which stores bile juice c) A structure which produces insulin hormone as well as digestive enzymes d) A vestigial organ e) The largest gland of the body f) Part where complete digestion takes place g) Part where water is absorbed PHYSICS Exercise for practice – Ch 1 1. What is the force that produces an acceleration of 1 m/s2 in a body of mass 1 kg ' [Ans. 1N] 2. Find the acceleration produced by a force of 5 N acting on a mass of 10 kg [0.5m/s2 3. A car of mass 2,400 kg moving with a velocity of 20 m/s is stopped in 10 seconds by applying brakes . calculate the retardation and the retarding force.[Ans. (i) -2 m/s2 (ii) -4,800N] 4. A force of 4 kg weight acts upon a body of mass 9.8 kg. Calculate the acceleration.[Ans. 4 m/s2] Note : 1 kg weight = 9.8 N. 5. A 1,000 kg vehicle moving with a speed of 20 m/s is brought to rest in a distance of 50m. (i) Find the acceleration; (ii) calculate the unbalanced force acting on the vehicle; (iii) the actual force applied may be slightly less than the calculated in (ii). Why ' Give reason.[Ans.(i) -4 m/s2 (ii)-4,000 N (iii) due to opposing force of friction between truck tyres and ground] 6. A force of 10 N acts upon a body of mass 2 kg. Calculate the acceleration.[Ans. 5 m/s2] 7. A body of mass 5 kg uniformly retards from 40m/s to 10m/s in 10s. Calculate the retarding force. [Ans. -15 N] 8. Calculate the force required to produce an acceleration of 5 ms-2 in a body of mass 6kg.[ Ans. 30 N] 9. A body of mass 10 kg is moving with a velocity of 20 ms-1. A force is applied on the body for 25 s, and it attains a velocity of 40 ms-2. What is the force applied '[Ans. 8N] 10. A certain force exerted for 1.2 seconds raises the speed of an object from 1.8 m/s to 4.2 m/s. Find its acceleration. If mass of the object was 5.5 kg. Calculate the force applied.[Ans.(i) 2 m/s2 (ii) 11 N] 11. What is the acceleration produced by a force of 12 newtons exerted on an object of mass 3 kg '[Ans. 4ms-2] 12. A force of 2 N acting on a body changes its velocity uniformly from 2 m/s to 5 m/s in 10s. Calculate the mass of the body.[Ans. 6.667 kg] 13. If 20 N force is applied on a 50 kg body in 0.5 second, find the impulse of the force given to the body.[Ans.10 Ns] 14. A cricket ball of mass 0.2 kg moving with a velocity of 20m/s is brought to rest by a player in 0.1 s. Find the impulse of the ball and the average force applied by the player.[ Ans. 4 Ns; 40 N] 15. A cricket ball of mass 300 g is moving at a speed of 90 km/h. The fielder stops it in a time interval of 2 seconds. Calculate the force exerted by the ball on the palm of fielder.[Ans. -3.75N] Exercise for practice – Ch 1 1. A body moving with a speed of 5 ms-1 is subjected to an acceleration of 20ms-1 . Calculate the speed of the body after 10 seconds. [Ans.205 m/s] 2. A car starting from rest attains a velocity of 60 km/h in 1 minute. Calculate : (i) its average velocity, (ii) acceleration, (iii) distance traveled during first 1 minute.[Ans. (i) 30 km/h ;(ii) 5/18 m/s2 (iii) 500m] 3. An aeroplane taking off from a field has a run of 500m. What is the acceleration, if it leaves the ground in 10 s '[ Ans. 10m/s2] 4. A train starting from stationary position and moving with uniform acceleration attains a speed of 36 km/h in 10 minutes. Find its acceleration.[Ans. 0.016 m/s2] 5. A bus increases its speed from 36 km/h to 72 km/h in 10 seconds. What is its acceleration '[Ans. 1 m/s2] 6. A scooter acquires a velocity of 36 km/h in 5 s just after the start. Calculate the acceleration of the scooter[ Ans.2m/s2]. 7. A bus traveling at 30 km/h speeds up to 60 km/h in 6 seconds. What is its acceleration in m/s2 '[Ans.1.389 m/s2 ] 8. Describe the motion of a body which is accelerating at a constant rate of 10 ms-2 . If the body starts from rest, how much distance will it cover in 2 s '[Ans.20m] 9. Find the initial velocity of a car which is stopped in 10 seconds by applying brakes. The retardation due to brakes is 2.5 ms2 . [Ans.25 m/s] 10. A body starting from rest travels with uniform acceleration. 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