To reduce the internal energy U of an ideal gas you need the gas to lose heat and/or do work.
Answer:
B. The mass of Mars is less than the mass of Earth.
Explanation:
Mass of an object is the constant anywhere in the universe.
The weight of an object is equal to the gravitational force acting on it.
Weight is given by

where
G = Gravitational constant
M = Mass of Planet
R = Radius of planet
m = Mass of object
g = Acceleration due to gravity
So weight of an object depends on the acceleration due to gravity on that planet. The acceleration due to gravity depends on the mass and radius of the planet.
The weight of the object is less on Mars because mars has less mass compared to Earth.
Explanation:
Given that,
Mass of the object, m = 7.11 kg
Spring constant of the spring, k = 61.6 N/m
Speed of the observer, 
We need to find the time period of oscillation observed by the observed. The time period of oscillation is given by :

Time period of oscillation measured by the observer is :

So, the time period of oscillation measured by the observer is 5.79 seconds.
The charge of the copper nucleus is 29 times the charge of one proton:

the charge of the electron is

and their separation is

The magnitude of the electrostatic force between them is given by:

where

is the Coulomb's constant. If we substitute the numbers, we find (we can ignore the negative sign of the electron charge, since we are interested only in the magnitude of the force)
Answer:

Explanation:
The vertical component of the initial velocities are

If we ignore air resistance, and let g = -9.81 m/s2. The the time it takes for the projectiles to travel, vertically speaking, can be calculated in the following motion equation




So the ratio of the times of the flights is
