- A. Metre scale
- B. Metre rod
- C. plastic ruler
- D. Measuring tape.
(d) Measuring tape.
- A. 70 cm
- B. 7 cm
- C. 700 cm
- D. 7000 cm
(c) 700 cm
- A. Physical quantity
- B. Measurement
- C. Unit
- D. Motion.
(b) Measurement
- A. km > mm > cm > m
- B. km> mm> m > cm
- C. km>m>cm>mm
- D. km > cm > m > mm
(c) km > m > cm > mm
- A. Left side of the point.
- B. Vertically above the point where the measurement is to be taken.
- C. Right side of the point.
- D. Anywhere according to one’s convenience.
When measuring the length of an object using a ruler, the position of your eye should be vertically above the point where the measurement is to be taken. This is important because if your eye is positioned at an angle to the scale, you will get an incorrect reading due to parallax error. Parallax error occurs when the line of sight is not perpendicular to the scale, causing the reading to appear different from different viewing angles. By keeping your eye directly above the point of measurement, you ensure that you are reading the scale at a right angle, which gives you the most accurate measurement possible. This practice is essential for obtaining precise measurements in scientific work and everyday applications.
False. Mass is a measure of the amount of matter in an object, and it is measured in kilograms (kg) or grams (g). While the statement mentions 126 kg, it incorrectly associates it with the length of one's chest. False. The length of one's chest is typically measured using a measuring tape or a flexible ruler, not a metre scale, which is designed for longer distances. True. Ten millimetres are indeed equivalent to one centimetre (1 cm = 10 mm). False. A hand span is a traditional unit of length but is not considered a reliable measure because it varies from person to person. True. The International System of Units (SI) is the modern form of the metric system and is the most widely accepted system of measurement globally.
metre
0.5
Kilometre
100
5000
Sugar is measured using a beam balance to determine its mass or weight. Lime juice is measured using a graduated cylinder because it is a liquid and volume measurement is appropriate. The height of a person is measured in centimetres (cm). The length of a sharpened pencil lead is measured in millimetres (mm) because of its small size. Milk, being a liquid, is measured by volume using a graduated cylinder or measuring cup. Vegetables are typically measured by their weight or mass using a beam balance or weighing scale. Different quantities require different measuring instruments and units depending on whether we are measuring mass, length, or volume.
In order from smallest to largest, the units of length are arranged as follows: 1 millimetre, 1 centimetre, 1 metre, and 1 kilometre. A millimetre is the smallest unit among these, followed by the centimetre which is 10 times larger than a millimetre. A metre is 100 times larger than a centimetre, and a kilometre is 1000 times larger than a metre. This arrangement helps us understand the relative sizes of different length measurements used in various contexts.
millimeter
Second
Parallax
Time
mass
Accurate
Length
Odometer
tape
litres
An International System of unit
Beam Balance
Kilogram.
Kilogram
The two parts present in a measurement are the numerical value and the unit. The numerical value tells us how many times the unit is contained in the quantity being measured, while the unit specifies what standard quantity is being used for the comparison. For example, in the measurement 5 metres, 5 is the numerical value and metre is the unit.
Measurement is the comparison of an unknown quantity with some known quantity of the same kind. It involves using a standard unit or scale to determine the size, length, mass, volume, or other properties of an object or substance. Measurement is fundamental to science and everyday life as it allows us to quantify and compare different things accurately.
Mass is the measure of the amount of matter in an object. It is an intrinsic property of an object that remains constant regardless of its location or the gravitational field acting on it. Mass is different from weight, which depends on gravity. The SI unit of mass is the kilogram.
(a) Convert km into metre
1 km = 1000m
∴ 43.65 km = 43.65 × 1000 = 43650.00 = 43650
= 43650 m.
(b) Convert km into cm.
1 km = 1000 m
1 m = 100 cm
1 km = 1000 × 100 cm
1 km = 100000 cm
∴ 43.65 km = 43.65 × 100000 = 4365000.00
= 4365000 cm.
To make an accurate measurement with a scale, several important rules must be followed. First, always ensure that the object being measured is placed parallel to the scale so that it aligns properly with the markings. Second, start the measurement from the zero mark of the scale rather than from the edge, as this ensures accuracy and avoids errors. Third, take care to read the correct submultiple or division on the scale, as misreading can lead to significant errors. Additionally, keep your eye vertically above the point of measurement to avoid parallax error, which occurs when viewing the scale from an angle. Finally, ensure that the scale is placed on a flat surface and that the object is not bent or curved, as this would affect the accuracy of the measurement.
Distance between school and house is 2250 m.
1000 m = 1 km
∴ 2250 m = 2250 ÷ 1000 = 2.25 km.
Sharpened pencil Reading at one end = 2.0 cm.
Sharpened pencil Reading at the other end = 12.1 cm.
Length of the pencil = Difference between two ends.
= 12.1 cm. – 2.0 cm.
= 10.1 cm.
Measuring the length of a curved line, by two methods.
First method – using a string.
Draw a curved line AB on the paper.
Place a string along the curved line.
Make sure that the string covers every bit of the curved line.
Mark the points where the curved line begins and ends on the string.
Now stretch the string along the length of a meter scale.
Measure the distance between two markings of the string.
This will give the length of a curved line.
Second method – using a divider.
Draw a curved line AB on a paper.
Separate the legs of the divider by 0.5 cm or 1 cm using a ruler.
Place it on the curved line starting from one end. Mark the position of the other end.
Move it along the line again and again cutting the line into a number of segments of equal lengths.
The remaining parts of the line can be measured using a scale.
Count the number of segments.
Length of the line = (No. of segments × length of each segment) + length of the leftover part.
- A. mass
- B. length
- C. time
- D. None
(b) length
- A. metre
- B. litre
- C. second
- D. kilogram.
(a) metre
-78 m, 75 cm
-1 km, 195 m
-160 mm
-45033 m
-1790
The SI units of length, mass, and time are as follows. Length is measured in metres, abbreviated as m. Mass is measured in kilograms, abbreviated as kg. Time is measured in seconds, abbreviated as s. These are the fundamental units in the International System of Units used universally for scientific measurements and calculations.
An electronic clock or a stop clock is used to measure time accurately. An electronic clock provides precise digital or analog time display with high accuracy, while a stop clock is specifically designed to measure short time intervals with precision, making it useful for timing experiments and activities in scientific work.
The hand holding the book will feel heavy. This is because the book has a greater mass than a single sheet of paper. According to the concept of weight, the gravitational force acting on an object is directly proportional to its mass. Since the book has more mass, the Earth's gravitational pull on it is stronger, resulting in greater weight. Therefore, the book exerts a greater downward force on the hand holding it. To support this greater force and keep the book in your hand without dropping it, your hand must exert an equal and opposite upward force. This greater effort required by the hand muscles to counteract the larger gravitational force makes the hand feel heavier when holding the book compared to holding a light sheet of paper. The sheet of paper, having negligible mass, exerts very little gravitational force, so the hand holding it feels almost no weight.