Question

A ball is projected horizontally from a tower with a velocity of 4m/s.Find the velocity of the ball after 0.70 seconds and acceleratio due to gravity=10m/s.

Answer 1

for horizontal component 
      v = u + at 
but in horizontal acceleration = 0 
so, v = u = 4m/s 

again,
 velocity in vertical direction,
 v = u + at 
here , u = 0 and a = - g = -10 m/s²
so, v = -10× 0.7 = -7 m/s

in vector from final velocity = 4 i - 7j
hence magnitude of velocity = √(4² +7²) = √65 = 8.06 m/s 

Answer 2

answer :--=--=: 8ms-1..........