Answer:
0.686 g of ice melts each second.
Solution:
As per the question:
Cross-sectional Area of the Copper Rod, A = 
Length of the rod, L = 19.6 cm = 0.196 m
Thermal conductivity of Copper, K = 
Conduction of heat from the rod per second is given by:

where
= temperature difference between the two ends of the rod.
Thus

Now,
To calculate the mass, M of the ice melted per sec:

where
= Latent heat of fusion of water = 333 kJ/kg

Answer:
800 meters per hour
Explanation:
800 meters per hour is the average speed of an airplane that travels from New York to Los Angeles, a total distance of 4800 km, in 6.0 hours.
Since Astronaut and wrench system is isolated in the space and there is no external force on it
So here momentum of the system will remain conserved
so here we can say

initially both are at rest
so here plug in all values


so here the astronaut will move in opposite direction and its speed will be equal to 0.20 m/s
Power = Work done/Time taken
So, keeping this in mind,we can solve it as follows:
= 700/3.1
= 7000/31
= 225.80 W