Answer:
Option A. 180000 Kgm/s.
Explanation:
From the question given above, the following data were obtained:
For Train Car A:
Mass of train car A = 45000 Kg
Velocity of train car A = 4 m/s
Momentum of train car A =?
For Train Car B:
Mass of train car B = 45000 Kg
Velocity of train car B = 0 m/s
Momentum is simply defined as the product of mass and velocity. Mathematically, it can be expressed as:
Momentum = mass × velocity
With the above formula, the momentum of train car A before collision can be obtained as follow:
Mass of train car A = 45000 Kg
Velocity of train car A = 4 m/s
Momentum of train car A =?
Momentum = mass × velocity
Momentum = 45000 × 4
Momentum of train car A = 180000 Kgm/s
Answer:
Echoes are the reflection of sound from relatively flat object that is far enough away that you can discern the time difference. Echoes are used to measure distance, velocity, and the shape of objects. Echoes off gratings result in an unusual pinging sound
Answer:
the capacitive reactance is reduced by a factor 2
Explanation:
The capacitive reactance is given by:

where
f is the frequency of the source
C is the capacitance
In this case, the frequency of the source is doubled:
f' = 2f
while the capacitance does not change. So the new capacitive reactance will be

so the capacitive reactance is reduced by a factor 2.
Answer:

Explanation:
Let consider that the person hit the ground in the negative direction. The physical model for the impact is modelled after the Impact Theorem:

The impact is:



The force of impact is derived as follows:



They are commonplaces because they have deep cracks where magma can come from. And we all know that igneous rock is molten lava that has been cooled, so this answer will make sense.