Chapter 12: How Heavy? How Light?

Answer: Both have equal weight.

NCERT book Page No: 139

Dinesan Went Shopping

Dinesan went to a shop and bought some things.

His younger brother cut the end of the bill where the weights were written.

Answer: The weights of the given items are as follows:

Answer: This can be done by keeping the tractor and car in each of the pan of the balance separately. By this, we come to know that the toy which goes down is the heavier toy among these two.

(b) Guess which is the heaviest a real car, a bus or a tractor?

Answer: A bus is the heaviest.

(c) Which is the heaviest thing you have seen?

Answer: The heaviest thing I have seen is a rail engine.

NCERT book Page No: 140

Elephant’s Weight

Answer: First, Vaidika’s daughter marked how much the boat sank in the river. She then asked them to bring the elephant into the boat. Now, the boat sank deeper, and she marked the new water level on the boat. She requested the king to put the gold on the boat till the water level touches the new raised water level mark when the elephant was on the boat. Now, the king was left with no alternative and had to give the gold equal to the weight of the elephant to Vaidika.

NCERT book Page No: 143

How Much the Chair Weighs

Answer: First, Anamika should put a flat wooden slab on the weighing machine, on which the chair can be kept easily and record its weight. Then she should place the chair on the slab kept on the weighing machine. The difference in the weight of the chair with the wooden slab and the weight of the wooden slab will give the weight of the chair.

NCERT book Page No: 143

Answer: By keeping a broken stone of 6 kg on the left pan and a broken stone of 2 kg on the right pan with firewood, he can weigh 4 kg of wood. Their difference, i.e.,

6 – 2 = 4 kg will give the weight of firewood.

(b) 3 kg of firewood

Answer: He can weigh 3 kg of firewood by keeping the broken stone of 5 kg on the left pan and the broken stone of 2 kg on the right pan with firewood. The difference in weight, i.e., 5 – 2 = 3 kg, will balance the two pans of balance by firewood.

(c) 7 kg of firewood

Answer: He can weigh 7 kg of firewood by keeping the broken stone of 5 kg and 2 kg on the left pan and firewood on the right pan.

NCERT book Page No: 145

Post Office

Answer: Yes.

Answer: People go to the post office for the following reasons:

(i) To post the letters

(ii) To send money orders

(iii) For banking

(iv) To purchase postcards, inland envelop, stamps, etc.

Answer: The cost of the postcard is Rs 0.50.