Classify the following as motion along a straight line, circular or oscillatory motion:
(i) Motion of your hands while running.
(ii) Motion of a horse pulling a cart on a straight road.
(iii) Motion of a child in a merry-go-round.
(iv) Motion of a child on a see-saw.
(v) Motion of the hammer of an electric bell.
(vi) Motion of a train on a straight bridge.
(i) Oscillatory motion Motion of our hands while running is oscillatory because while running our hands does to and froth motion in the same interval of time, is called oscillatory motion and is also called Periodic motion. The swinging of a pendulum is an example of periodic motion.
(ii) Straight line motion If an object changes its position with respect to its surroundings with time, then it is called in motion. It is the straight line motion because in this the object changes its position along the straight line with respect to time. For example: car is running on the straight road.
(iii) Circular motion When an object moves along a circular path without changing its position, it is called circular motion. For example: the earth moves around the sun in a circular path in its particular orbit, so the motion of the earth around the sun is circular motion; ceiling fan, wheel of the bicycle.
(iv) Oscillatory motion The motion which repeats itself after regular intervals of time, is called oscillatory motion and also called Periodic motion. The swinging of a pendulum is an example of periodic motion; swinging of the swing, vibration of the mobile phone etc.
(v) Oscillatory motion The motion which repeats itself after regular intervals of time, is called oscillatory motion. When the hammer hits the electric bell then it vibrates repetitively, so this repetitively motion is oscillatory motion.
(vi) Straight line motion If an object changes its position with respect to its surroundings with time, then it is called in motion. In this, the train is moving on the straight bridge, it shows the change in position of the train along the straight line that shows straight line motion.
Suppose the two photographs, shown in Fig. 13.1 and Fig. 13.2, had been taken at an interval of 10 seconds. If a distance of 100 metres is shown by 1 cm in these photographs, calculate the speed of the blue car.
The distance between two stations is 240 km. A train takes 4 hours to cover this distance. Calculate the speed of the train.
A simple pendulum takes 32 s to complete 20 oscillations. What is the time period of the pendulum?
Salma takes 15 minutes from her house to reach her school on a bicycle. If the bicycle has a speed of 2 m/s, calculate the distance between her house and the school.
The odometer of a car reads 57321.0 km when the clock shows the time 08:30 AM. What is the distance moved by the car, if at 08:50 AM, the odometer reading has changed to 57336.0 km? Calculate the speed of the car in km/min during this time. Express the speed in km/h also.
Show the shape of the distance-time graph for the motion in the following cases:
(i) A car moving with a constant speed.
(ii) A car parked on a side road.
Which of the following distance-time graphs shows a truck moving with speed which is not constant?
Fig. 13.15 shows the distance-time graph for the motion of two vehicles A and B. Which one of them is moving faster?
Fig. 13.15 Distance-time graph for the motion of two cars
Which of the following are not correct?
(i) The basic unit of time is second.
(ii) Every object moves with a constant speed.
(iii) Distances between two cities are measured in kilometres.
(iv) The time period of a given pendulum is not constant.
(v) The speed of a train is expressed in m/h.
Which of the following relations is correct?
(i) Speed = Distance × Time (ii) Speed = Distance
Time
(iii) Speed = Time (iv) Speed = 1
Distance Distance × Time
State similarities and differences between the laboratory thermometer and the clinical thermometer.
State differences between acids and bases.
Classify the changes involved in the following processes as physical or chemical changes:
(a) Photosynthesis
(b) Dissolving sugar in water
(c) Burning of coal
(d) Melting of wax
(e) Beating aluminium to make aluminium foil
(f ) Digestion of food
Name the elements that determine the weather of a place.
Fill the missing word in the blank spaces in the following statements:
(a) Wind is——————air.
(b) Winds are generated due to —————— heating on the earth.
(c) Near the earth’s surface __________air rises up whereas ___________ air comes down.
(d) Air moves from a region of ——— pressure to a region of ———.
In addition to the rock particles, the soil contains
(i) air and water
(ii) water and plants
(iii) minerals, organic matter, air and water
(iv) water, air and plants
Why does an athlete breathe faster and deeper than usual after finishing the race?
Match structures given in Column I with functions given in Column II.
Column I Column II
(i) Stomata (a) Absorption of water
(ii) Xylem (b) Transpiration
(iii) Root hairs (c) Transport of food
(iv) Phloem (d) Transport of water
(e) Synthesis of carbohydrates
Fill in the blanks:
(a) Production of new individuals from the vegetative part of parent is called_____________.
(b) A flower may have either male or female reproductive parts. Such a flower is called_____________.
(c) The transfer of pollen grains from the anther to the stigma of the same or of another flower of the same kind is known as _____________.
(d) The fusion of male and female gametes is termed as _____________.
(e) Seed dispersal takes place by means of _____________, _____________ and _____________.
Why do organisms need to take food?
Out of the following, which are the two terms related to silk production? Sericulture, floriculture, moriculture, apiculture and silviculture.
Hints:
(i) Silk production involves cultivation of mulberry leaves and rearing silkworms.
(ii) Scientific name of mulberry is Morus alba.
Name two chemicals used to disinfect water.
Three liquids are given to you. One is hydrochloric acid, another is sodium hydroxide and third is a sugar solution. How will you identify them? You have only turmeric indicator.
Tick the correct answer:
(a) In cockroaches, air enters the body through
(i) lungs (ii) gills
(iii) spiracles (iv) skin
(b) During heavy exercise, we get cramps in the legs due to the accumulation of
(i) carbon dioxide (ii) lactic acid
(iii) alcohol (iv) water
(c) Normal range of breathing rate per minute in an average adult person at rest is:
(i) 9ñ12 (ii) 15ñ18
(iii) 21ñ24 (iv) 30ñ33
(d) During exhalation, the ribs
(i) move outwards (ii) move downwards
(iii) move upwards (iv) do not move at all
Why is transport of materials necessary in a plant or in an animal? Explain.
Match the items in Column I with those in Column II:
Column I Column II
(a) Yeast (i) Earthworm
(b) Diaphragm (ii) Gills
(c) Skin (iii) Alcohol
(d) Leaves (iv) Chest cavity
(e) Fish (v) Stomata
(f) Frog (vi) Lungs and skin
(vii) Tracheae
Blue litmus paper is dipped in a solution. It remains blue. What is the nature of the solution? Explain.
Describe the function of the heart.
Explain the difference between self-pollination and cross-pollination.
Zubeda made an electric circuit using a cell holder shown in Fig. 14.4, a switch and a bulb. When she put the switch in the ‘ON’ position, the bulb did not glow. Help Zubeda in identifying the possible defects in the circuit.