Question

The P.E and K.E of a helicopter flying horizontally at a height 400m are in the ratio 5:2 .then velocity of helicopter

Answer 1

pe =mgh
ke=1/2mv^2

pe/ke=mgh/1/2mv^2=5/2

2gh/v^2=5/2
v=(4gh/5) square root of bracket
v=(4×9.8×400/5) square root
v=56m/sec

Answer 2

P.E = mgh

K.E = 1/2mv²

So

mgh/1/2mv²

mgh/1/2/mv² 5/2

= 2gh /v² = 5/2

v = √ ( 4gh/5)²

v =√ ( 4 × 9.8 × 400/5 )

v = 56m/s