A stone is projected vertically upward to reach maximum height h . The ratio of its kinetic energy to its potential energy at a height (4/5)h , will be

Question

A stone is projected vertically upward to reach maximum height h . The ratio of its kinetic energy to its potential energy at a height (4/5)h , will be (A) 5:4 (B) 4:5 (C) 1:4 (D) 4:1

Tardigrade Admin · Accepted Answer

At a height (4 h/5) , the potential energy of the stone will be, PE=mg((4 h/5))...(1) The total energy of the stone will be mgh , hence the kinetic energy of the particle will be, KE=mgh-(4/5)mgh=(m g h/5)...(2) From equation (1) and (2) , (K E/P E)=((m g h/5)/(4 m g h)5)=(1/4) .

Q. A stone is projected vertically upward to reach maximum height $h$ . The ratio of its kinetic energy to its potential energy at a height $\frac{4}{5} h$ , will be

$5 : 4$

$4 : 5$

$1 : 4$

$4 : 1$

Q. A stone is projected vertically upward to reach maximum height h . The ratio of its kinetic energy to its potential energy at a height 54​h , will be

5:4

4:5

1:4

4:1

At a height 54h​ , the potential energy of the stone will be, PE=mg(54h​)...(1) The total energy of the stone will be mgh , hence the kinetic energy of the particle will be, KE=mgh−54​mgh=5mgh​...(2) From equation (1) and (2) , PEKE​=54mgh​5mgh​​=41​ .

Q. A stone is projected vertically upward to reach maximum height $h$ . The ratio of its kinetic energy to its potential energy at a height $\frac{4}{5} h$ , will be

$5 : 4$

$4 : 5$

$1 : 4$

$4 : 1$