An apple drops from a tree and hits the ground in 1.5s what is its speed just before it hits the ground?

Vf - Vo = gT  

where  

Vf = velocity of apple just before hitting the ground  

Vo = initial velocity of apple = 0  

T = time for apple to hit the ground = 1.5 sec (given)  

g = acceleration due to gravity = 9.8 m/sec^2 (constant)  

Substituting appropriate values,  

Vf - 0 = 9.8(1.5)  

Vf = 14.7 m/sec.  

b.transmitters send radio waves, and receivers capture radio waves.