Answer:
An open system.
Explanation:
An isolated system allows the exchange of neither energy nor matter with the surroundings. A closed system allows the exchange of energy, but not matter. An open system allows the exchange of both energy and matter.
Notice that in this question, light (electromagnetic wave) is a form of energy. The entry and exit of light allows this system to exchange energy with its surroundings- just as how the earth receives energy from the sun. Additionally, this system could exchange energy with its surroundings through the exchange of matter (in particular, air) with its surroundings.
Thus, the system in this question is an open system.
Answer:
That is true, the hotter a star is the shorter of wavelength it emits and the higher. It also depends on the mass of the star because the bigger it is, the faster it fuses its hydrogen fuel. Faster burning of fuel means more energy is released and so results in higher temperatures.
Hope this helps! Good luck :)
Explanation:
Answer:
F_net = 26.512 N
Explanation:
Given:
Q_a = 3.06 * 10^(-4 ) C
Q_b = -5.7 * 10^(-4 ) C
Q_c = 1.08 * 10^(-4 ) C
R_ac = 3 m
R_bc = sqrt (3^2 + 4^2) = 5m
k = 8.99 * 10^9
Coulomb's Law:
F_i = k * Q_i * Q_j / R_ij^2
Compute F_ac and F_bc :
F_ac = k * Q_a * Q_c / R^2_ac
F_ac = 8.99 * 10^9* ( 3.06 * 10^(-4 ))* (1.08 * 10^(-4 )) / 3^2
F_ac = 33.01128 N
F_bc = k * Q_b * Q_c / R^2_bc
F_bc = 8.99 * 10^9* ( 5.7 * 10^(-4 ))* (1.08 * 10^(-4 )) / 5^2
F_bc = - 22.137 N
Angle a is subtended between F_bc and y axis @ C
cos(a) = 3 / 5
sin (a) = 4 / 5
Compute F_net:
F_net = sqrt (F_x ^2 + F_y ^2)
F_x = sum of forces in x direction:
F_x = F_bc*sin(a) = 22.137*(4/5) = 17.71 N
F_y = sum of forces in y direction:
F_y = - F_bc*cos(a) + F_ac = - 22.137*(3/5) + 33.01128 = 19.72908 N
F_net = sqrt (17.71 ^2 + 19.72908 ^2) = 26.5119 N
Answer: F_net = 26.512 N
Answer:
Surface tension in water
Friction between tires and pavement
Dissolution of salt in water
Explanation:
Surface tension in water: It is due to the electrostatic force of attraction (cohesive force) between water molecules.
Friction between tires and pavement: It is due to the attractive force between tires and pavement.
Dissolution of salt in water: The ions of 
and 
separate due to the strong attraction of water molecules.
