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Give two examples of elements,
compounds & mixtures each.
Answers
Explanation:
6. A train travels some distance with a speed of 30 km/h and returns with a speed of 45 km/h . Calculate the average speed of the train .
7. A train 100 m long moving on a straight level track passes a pole in 5 s . Find (a) the speed of the train (b) the time it will take in to cross a bridge 500 m long .
8. A car travels along a straight lion for first half time with speed 40 km/h and the second half time with speed 60 km/h. find the average speed of the car.
9. A body starts rolling over a horizontal surface with an initial velocity of 0.5 m/s² . Due to friction , its velocity decreases at the rate of 0.05 m/s² . How much time will it take for the body to stop ?
10. A car travelling at 36 km/h speed upto 72 km/h in 5 second. what is it acceleration ? If the same car stops in 20 second , what is the retardation ?
Answer:
- Common examples include carbon, sulfur, oxygen, iron, copper, aluminium. Elements are represented by symbols. Compounds are substances made from atoms of different elements joined by chemical bonds. They can only be separated by a chemical reaction.