train travels 40 km at a uniform speed of 30 km/hr. Its average speed after travelling another 40 km is 45 km/hr for the whole journey. It's speed in the second half of the journey is ?

Which of the following is a source of heat for magma formation? magma plumes in the continental crust friction due to divergence friction due to subduction magma plumes in the oceanic crust

The charge on an electron is 1.60218 × 10−19 c and its mass is 9.10939 × 10−31 kg. how strong a magnetic field must be experienced by the electron if its path is a circle of radius 5.5 cm? answer in units of t.

Acertain radio station broadcasts radio waves that have a wavelength of 298cm what is its broadcast frequency?