Answer:The correct options are:
1. A system is a group of objects analyzed as one unit.
2. Energy that moves across system boundaries is conserved.
Explanation:
A system is defined as group of interrelated or interacting items existing as a single unit or a whole to achieve a specific objective.Energy lost by the system is equal to the energy gained by the surroundings.
Two statements are true about a system:
- A system is a group of objects analyzed as one unit.
- Energy that moves across system boundaries is conserved.
According to the Law of Conservation of Energy, energy is neither created nor destroyed. They are just transferred from one system to another. To obey this law, the energy of the substances inside the container must be equal to the substance added to it. The energy is in the form of heat. There can be two types of heat energy: latent heat and sensible heat. Sensible heat is energy added or removed when a substance changes in temperature. Latent heat is the energy added or removed at a constant temperature during a phase change. Since there is no mention of phase change, we assume the heat involved here is sensible heat. The equation for sensible heat is:
H = mCpΔT
where
m is the mass of the substance
Cp is the specific heat of a certain type of material or substance
ΔT is the change in temperature.
So the law of conservation of heat tells that:
Sensible heat of Z + Sensible heat of container = Sensible heat of X
Since we have no idea what these substances are, there is no way of knowing the Cp. We can't proceed with the calculations. So, we can only assume that in the duration of 15 minutes, the whole system achieves equilibrium. Therefore, the equilibrium temperature of the system is equal to 32°C. The answer is C.
Answer:
Option (b) is correct.
Explanation:
The motion under the influence of gravity is called projectile motion.
The acceleration due to gravity is constant through out the motion and it is always acting downwards.
When an athlete jumps and follow the projectile path, it always have the same horizontal velocity as there is no acceleration in the horizontal direction.
Also he has the vertical acceleration constant which is equal to the acceleration due to gravity and acts towards the center of earth.
Option (b) is correct.
Answer:
2.5 times higher then that on the Earth
Explanation:
Gravity is higher on Jupiter then on Earth because Jupiter is much bigger, because of it's mass compared to Earth the gravity on Jupiter is about 2.4 - 2.5 times higher then Earths surface gravity which means a rock on Jupiter would be around "2.4 - 2.5 times as heavier then it would be on Earth."
Hope this helps.
The magnitude of Alioth ( the brightest star in the big dipper ) is 1.76 and it is about 81 light years distant from Earth.
