A staircase contains three steps each 10 cm high and 20 cm wide figure. What should be the minimum horizontal velocity of a bal rolling off the upper most plane so as to hit directly the lowest plane?

Answer

B

Explanation

At minimum velocity it wil move just touching the pint E and reaches the ground.
A is origin of referfences co - ordiN/Ate.

If u is the minimum speed.
`x= 40, y= -20, theta = 0^0`
`:. Y= tantheta -g (x^2 sec^2 theta)/(2u^2)`
where `g= 10 m/s^2 = 1000 cm/s^2`
`rarr -20= - 800000/(2u^2)`
`rarr u= 200 cm/s=2m/s` ltbr. `:.` the minimum horizontal velocity is 2m/s.