Answer:
<u>Chemical changes</u> are recognized when a substance changes its properties permanently and it cannot be the same substance as before.
Instead the<u> physical changes</u><u> </u>implies that if you can return to the same substance through a reverse process.
Explanation:
A chemical change is, by example, a combustion, if a sheet of paper burns, its result is ashes, the ashes cannot go back to being a sheet of paper because its properties changed, heat energy was generated that changed matter permanently.
A physical change, by example, is that of freezing water, the water becomes ice, but this can easily become water again if the temperature is increased, its properties do not change and the chemistry of the substance does not change.
Answer:
Explanation:
Angular momentum ( L ) = moment of inertia x angular velocity ( I X ω )
Moment of inertia of two 480 g masses about axle = 2 x mr² = 2 x 480 x10⁻³ x( 24 x 10 ⁻ 2 )² = 0. 552960 kg m².
Angular velocity = 5 rad / s.
Angular momentum = 0.552960 x 5 = 2.765 kg m2.
The direction of angular momentum will be along axle.So vector angular
momentum makes zero degree with axle.
Answer:
6) False
7) True
8) False
9) False
10) False
11) True
12) True
13) True
14) True
Explanation:
The spacing between two energy levels in an atom shows the energy difference between them. Clearly, B has a greater value of ∆E compared to A. This implies that the wavelength emitted by B is greater than A while B will emit fewer, more energetic photons.
When atoms jump from lower to higher energy levels, photons are absorbed. The kinetic energy of the incident photon determines the frequency, wavelength and colour of light emitted by the atom.
The energy level to which an atom is excited is determined by the kinetic energy of the incident electron. As the voltage increases, the kinetic energy of the electron increases, the further the atom is from the source of free electrons, the greater the required kinetic energy of free electron. When electrons are excited to higher energy levels, they must return to ground state.
Answer:
Momentum after collision will be 6000 kgm/sec
Explanation:
We have given mass of the whale = 1000
Initial velocity v = 6 m/sec
It collides with other mass of 200 kg which is at stationary
Initial momentum of the whale = 1000×6 = 6000 kgm/sec
We have to find the momentum after collision
From conservation of momentum
Initial momentum = final momentum
So final momentum = 6000 kgm/sec
Answer:
The second vector 
points due West with a magnitude of 600N
Explanation:
The original vector 
points with a magnitude of 200N due east, the Resultant vector 
points due west (that's how east/west direction can be interpreted, from east to west) with a magnitude of 400N. If we choose East as the positive direction and West as the negative one, we can write the following vectorial equation:
With the negative sign signifying that the vector points west.
