To solve this problem, we must remember about the law of
conservation of momentum. The initial momentum mist be equal to the final
momentum, that is:
m1 v1 + m2 v2 = (m1 + m2) v’
where v’ is the speed of impact
Since we are not given the masses of each car m1 and m2,
so let us assume that they are equal, such that:
m1 = m2 = m
Which makes the equation:
m v1 + m v2 = (2 m) v’
Cancelling m and substituting the v values:
50 + 48 = 2 v’
2 v’ = 98
v ‘ = 49 km/h
<span>The speed of impact is 49 km/h.</span>
Answer:
U₂ = 400 KJ
Explanation:
Given that
Initial energy of the tank ,U₁= 800 KJ
Heat loses by fluid ,Q= - 500 KJ
Work done on the fluid ,W= - 100 KJ
Sign -
1.Heat rejected by system - negative
2.Heat gain by system - Positive
3.Work done by system = Positive
4.Work done on the system-Negative
Lets take final internal energy =U₂
We know that
Q= U₂ - U₁ + W
-500 = U₂ - 800 - 100
U₂ = -500 +900 KJ
U₂ = 400 KJ
Therefore the final internal energy = 400 KJ
You pick a system for which no control sample exists, so that no one can show that the alleged causal relationships you assert do not, in fact, lead to the phenomenon you claim to have observed.
Answer:
This material exhibits paramagnetism.
Explanation:
A paramagnetic material has these features: It doesn’t have any magnetic properties when placed in an external magnetic field, it gains and then loses the magnetic property as the external field is removed.
Such materials have magnetic moments oriented in random directions, thus making the net magnetic moment, zero. But when placed in an external field, they do possess a net magnetic moment. When the magnetic field is removed, they lose the magnetic property.
Thus, the material which produces no initial magnetic field when placed in a uniform magnetic field produces an additional internal magnetic field parallel to the original field. Also, it loses the magnetic properties as soon as the external magnetic field is removed. Then, the magnetism the material exhibits is paramagnetic.
This is most likely an example of kinetic energy.
