a train covers half of its journey with a speed of 20 metre per second and the other of with the speed of 30 metre per second the average speed of the pain during the whole journey is

What do you think car designers do if the damage caused by a crash test is too severe?

Considering only the earth's rotation, determine how much later the asteroid would have had to arrive to put the explosion above helsinki at longitude 25˚ e? this would have obliterated the city.

Two pans of a balance are 24.1 cm apart. the fulcrum of the balance has been shifted 1.33 cm away from the center by a dishonest shopkeeper. by what percentage is the true weight of the goods being marked up by the shopkeeper? assume the balance has negligible mass. answer in units of %.