Question

A stationary object at $4{}^\circ C$ and weighing 3.5 kg falls from a height 2000 m on a snow mountain at $0{}^\circ C$ . If the temperature of the object just before hitting the snow is $0{}^\circ C$ and the object before comes to rest immediately $(g=10\text{ }m/{{s}^{2}})$ and latent heat of ice $=3.5\times {{10}^{5}}$ J/s), then the object

• A. 2kg of ice
• B. 200 g of ice
• C. 20g ice
• D. 2g ice

Answer 1

Answer: (B)

200 g of ice

Answer 2

Law of conservation of energy is valid. Potential energy is the energy possesed by a body due. to its weight. It is given by $PE=mgh$ where, m is mass, g acceleration due to gravity and h is height This potential energy is utilized in giving latent heat to ice $mL=mgh$ Given $~m=3.5kg,\text{ }g=10m/{{s}^{2}},\text{ }h=2000m$ $L=3.5\times {{10}^{5}}J/s$ $m=\frac{mgh}{L}$ $m=\frac{3.5\times 10\times 200}{3.5\times {{10}^{5}}}$ $m=02$ kg of ice Also, $1\,kg={{10}^{3}}g$ $m=200\text{ }g$ of ice