Question

FIND THE HEIGHT AT WHICH K.E IS 1/4TH OF P.E WHEN A NASS IS DROPPED AT A HEIGHT OF 20M. ALSO FIND VELOCITY AT THIS POINT.​

please ans .meee

Answer 1

K.E=P.E/4

at maximam height P.E is max & K.E=0

let x be the height

then

V²=2gx

K.E=1/2 mv²

=1/2 ×m×2gx=mgx

P.E=mgh

=mg×(20-x)

=20mg-mgx

GIVEN

mg×(20-x)/4=mgx

⇒mg(20-x)= 4mgx

⇒g(20-x)=4gx

⇒9.8×20-9.8x=39.2x

⇒196=39.2x+9.8x=49x

⇒x=196/49=4 m