Answer:
6.86 × 10²⁴ kg
Explanation:
The mass of the earth m = density of earth, ρ × volume of earth, V
m = ρV
The density of the earth, ρ = 5515 kg/m³ and since the earth is a sphere, its volume is the volume of a sphere V = 4πr³/3 where r = radius of the earth = 6.67 × 10⁶ m
Since m = ρV
m = ρ4πr³/3
So, substituting the values of the variables into the equation for the mass of the earth, m, we have
m = 5515 kg/m³ × 4π(6.67 × 10⁶ m)³/3
m = 5515 kg/m³ × 4π × 296.741 × 10¹⁸ m³/3
m = 5515 kg/m³ × 1189.9639π × 10¹⁸ m³/3
m = 6546105.64378π × 10¹⁸ kg/3
m = 20565197.400122 × 10¹⁸ kg/3
m = 6855065.8 × 10¹⁸ kg
m = 6.8550658 × 10²⁴ kg
m ≅ 6.86 × 10²⁴ kg
Cars 'A' and 'C' look like they're moving at the same speed. If their tracks are parallel, then they're also moving with the same velocity.
Answer: Option (b) is the correct answer.
Explanation:
The given data is as follows.
F =
N
g = 9.8 m/s
radius =
=
= 15 cm = 0.15 m (as 1 m = 100 cm)
Formula to calculate depth is as follows.
F = 
or, h =
h =
= 751 m
Thus, we can conclude that the maximum depth in a lake to which the submarine can go without damaging the window is closest 750 m.
Answer:
The latent heat of fusion of water is 334.88 Joules per gram of water.
Explanation:
Let the latent heat of ice be 'x' J/g
1) Thus heat absorbed by 100 gram of ice to get converted into water equals

2) heat energy required to raise the temperature of water from 0 to 25 degree Celsius equals

Thus total energy needed equals 
3) Heat energy released by the decrease in the temperature of water from 25 to 11 degree Celsius is

Now by conservation of energy we have

Answer:
Magnification, m = -0.42
Explanation:
It is given that,
Height of diamond ring, h = 1.5 cm
Object distance, u = -20 cm
Radius of curvature of concave mirror, R = 30 cm
Focal length of mirror, f = R/2 = -15 cm (focal length is negative for concave mirror)
Using mirror's formula :
, f = focal length of the mirror


v = -8.57 cm
The magnification of a mirror is given by,


m = -0.42
So, the magnification of the concave mirror is 0.42. Thew negative sign shows that the image is inverted.