A ball of mass 2kg and another of mass 4kg are dropped together from a 60ft tall building. After a fall of 30ft each towards earth, their respective kinetic energies will be in the ratio of

Question

A ball of mass 2kg and another of mass 4kg are dropped together from a 60ft tall building. After a fall of 30ft each towards earth, their respective kinetic energies will be in the ratio of (A) 1:√2 (B) √2:1 (C) 1:4 (D) 1:2

Tardigrade Admin · Accepted Answer

Since travelling distance is same for both balls, their velocities at the end of 30 feet journey will be same ∴ (K . E1/K . E2)=((1/2) m1 v02/(1)2 m2 v02)=(m1/m2)=(2/4)=(1/2)

Q. A ball of mass $2 k g$ and another of mass $4 k g$ are dropped together from a $60 f t$ tall building. After a fall of $30 f t$ each towards earth, their respective kinetic energies will be in the ratio of

$1 : 2$

$2 : 1$

$1 : 4$

$1 : 2$

Since travelling distance is same for both balls, their velocities at the end of 30 feet journey will be same
$∴ \frac{K . E _{1}}{K . E _{2}} = \frac{\frac{1}{2} m _{1} v _{0}^{2}}{\frac{1}{2} m _{2} v _{0}^{2}} = \frac{m _{1}}{m _{2}} = \frac{2}{4} = \frac{1}{2}$

Q. A ball of mass 2kg and another of mass 4kg are dropped together from a 60ft tall building. After a fall of 30ft each towards earth, their respective kinetic energies will be in the ratio of

1:2​

2​:1

1:4

1:2

Since travelling distance is same for both balls, their velocities at the end of 30 feet journey will be same ∴K.E2​K.E1​​=21​m2​v02​21​m1​v02​​=m2​m1​​=42​=21​

Q. A ball of mass $2 k g$ and another of mass $4 k g$ are dropped together from a $60 f t$ tall building. After a fall of $30 f t$ each towards earth, their respective kinetic energies will be in the ratio of

$1 : 2$

$2 : 1$

$1 : 4$

$1 : 2$

Since travelling distance is same for both balls, their velocities at the end of 30 feet journey will be same
$∴ \frac{K . E _{1}}{K . E _{2}} = \frac{\frac{1}{2} m _{1} v _{0}^{2}}{\frac{1}{2} m _{2} v _{0}^{2}} = \frac{m _{1}}{m _{2}} = \frac{2}{4} = \frac{1}{2}$