D. physical property
the bonds between molecules of mercury are breaking so it's physical and it's not changing the chemical composition of the substance
Answer:
The work done to get you safely away from the test is 2.47 X 10⁴ J.
Explanation:
Given;
length of the rope, L = 70 ft
mass per unit length of the rope, μ = 2 lb/ft
your mass, W = 120 lbs
mass of the 70 ft rope = 2 lb/ft x 70 ft
= 140 lbs.
Total mass to be pulled to the helicopter, M = 120 lbs + 140 lbs
= 260 lbs
The work done is calculated from work-energy theorem as follows;
W = Mgh
where;
g is acceleration due gravity = 32.17 ft/s²
h is height the total mass is raised = length of the rope = 70 ft
W = 260 Lb x 32.17 ft/s² x 70 ft
W = 585494 lb.ft²/s²
1 lb.ft²/s² = 0.0421 J
W = 585494 lb.ft²/s² = 2.47 X 10⁴ J.
Therefore, the work done to get you safely away from the test is 2.47 X 10⁴ J.
Answer:
Explanation:
a )
hear energy required to melt 1 g of ice = 340 J ,
hear energy required to melt 80 g of ice = 340 x 80 J = 27220 J .
b ) energy gained by the melted ice ( water at O°C ) = m ct
where m is mass of water , s is specific heat and t is rise in temperature
= 80 x 4.2 x ( 8°C - 0°C)
= 2688 J .
c )
energy lost by lime juice = energy gained by ice and water
= 27220 J + 2688 J .
= 29908 J .
d )
Let specific heat required be S
Heat lost by lime juice = M S T
M is mass of lime juice , S is specific heat , T is decrease in temperature
= 320 g x S x ( 29 - 8 )°C
= 6720 S
For equilibrium
Heat lost = heat gained
6720 S = 29908 J
S = 4.45 J /g °C .
Average velocity is 1..2 mi/min east
Explanation:
- Velocity = Displacement/Time
Here, displacement = 48 mi - 42 mi = 6 miles
Time = 5 minutes
⇒ Average Velocity = 6/5 = 1.2 mi/min east
