A 50 kg surfer is riding a 25 kg surfboard at a speed of 6.00 m/s and then jumps off the front, moving forward. The surfers velocity when jumping off the surfboard is 2.50 m/s. Find the surfboards velocity immediately after the surfer jumps off.

The relationship of both of them

Planck decided to assume that atoms could only vibrate at certain frequencies that were whole numbers eg 2f, 3f and so on. others used to think that atoms vibrate continuously

Year  1936,  lehman predicted that the earths 'inner core' is solid. she observed that the seismic signals during her study were bent and did not pass through instead bouncing back. later it was confirmed that the earth's inner core was solid made up of nickel-iron and had a molten outer core.