By what fraction does the mass of a boy increase when he starts running at a speed of `12 km h ^(-1)?

By what fraction does the mass of an H atom decreases when it makes an n=3 to n=1 transition ?

How many minutes does Vishwa take to cover a distance of 1300 m if he runs at a speed of 26 km h?

A train 100m long is running at a speed of 70 km/h. In what time will it pass a man who is running at a speed of 10 km/h in the same direction?

A thief is spotted by a policeman from a distance of 100 metres.When the policeman starts the chase,the thief also starts running. If the speed of the thief be 8km/hr and that of the policeman 10km/hr ,how far the thief will have run before he is overtaken?

A thief is spotted by a policeman from a distance of 100 m. When the policeman starts the chase, the thief also starts running. If the speed of the thief is 8 km/hour and that of the policeman is 10 km/hour, then how far will the thief have to run before he is overtaken?