Answer A, low energy and long wavelength.
Answer:
hai điện tích điểm bằng nhau có độ lớn 6.10^-8C đặt cách nhau một khoảng là r trong dầu hỏa có hằng số điện môi E=2,1. Lực tương tác tĩnh điện giữa chúng laf3,85.10^-4. tìm r
Copper is a reddish orange, soft metal with a bright metallic luster. It is an excellent conductor of heat and electricity. Copper surfaces when exposed to air gradually turns to a dull, brownish color.
Answer
given,
mass of the ski = 75 Kg
speed of the skier, v = 3 m/s
time = 1.50 min = 90 s
angle of inclination, θ = 40°
distance = s x t
= 3 x 90 = 270 m
a) W = F. d cos θ
W = mg. d cos θ
W = 75 x 9.8 x 270 x cos 40°
W = 152021.52 J
work is done by the ski lift is equal to 152021.52 J
b) Power extended by the ski
P = 1689.13 Watt.
power is expended by the ski lift is equal to 1689.13 W.
Answer:
R = 98304.75 m = 98.3 km
Explanation:
The density of an object is given as the ratio between the mass of that object and the volume occupied by that object.
Density = Mass/Volume
Now, it is given that the density of Earth has become:
Density = 1 x 10⁹ kg/m³
Mass = Mass of Earth (Constant) = 5.97 x 10²⁴ kg
Volume = 4/3πR³ (Volume of Sphere)
R = Radius of Earth = ?
Therefore,
1 x 10⁹ kg/m³ = (5.97 x 10²⁴ kg)/[4/3πR³]
4/3πR³ = (5.97 x 10²⁴ kg)/(1 x 10⁹ kg/m³)
R³ = (3/4)(5.97 x 10¹⁵ m³)/π
R = ∛[0.95 x 10¹⁵ m³]
<u>R = 98304.75 m = 98.3 km</u>
