Answer:
The work done is zero
Explanation:
No work is performed or required in moving the positive charge from point A to point B
Answer:
335°C
Explanation:
Heat gained or lost is:
q = m C ΔT
where m is the mass, C is the specific heat capacity, and ΔT is the change in temperature.
Heat gained by the water = heat lost by the copper
mw Cw ΔTw = mc Cc ΔTc
The water and copper reach the same final temperature, so:
mw Cw (T - Tw) = mc Cc (Tc - T)
Given:
mw = 390 g
Cw = 4.186 J/g/°C
Tw = 22.6°C
mc = 248 g
Cc = 0.386 J/g/°C
T = 39.9°C
Find: Tc
(390) (4.186) (39.9 - 22.6) = (248) (0.386) (Tc - 39.9)
Tc = 335
12 is correct
Explanation: it's a cube
Answer:
The correct answer is a. Both are the same
Explanation:
For this calculation we must use the gravitational attraction equation
F = G m M / r²
Where M will use the mass of the Earth, m the mass of the girl and r is the distance of the girl to the center of the earth that we consider spherical
To better visualize things, let's repair the equation a little
F = m (G M / r²)
The amount in parentheses called acceleration of gravity, entered the force called peos
g = G M / r²
F = W
W = m g
When analyzing this equation we see that the variation in the weight of the girl depends on the distance, which is the radius of the earth plus the height where the girl is
r = Re + h
Re = 6.37 10⁶ m
r² = (Re + h)²
r² = Re² (1 + h / Re)²
Let's replace
W = m (GM / Re²) (1+ h / Re)⁻²
W = m g (1+ h / Re)⁻²
This is the exact expression for weight change with height, but let's look at its values for some reasonable heights h = 6300 m (very high mountain)
h / Re = 10
⁻³
(1+ h / Re)⁻² = 0.999⁻²
Therefore, the negligible weight reduction, therefore, for practical purposes the weight does not change with the height of the mountain on Earth
The correct answer is a
