Answer:

Explanation:
We must separate the motion into two parts, the first when the rocket's engines is on and the second when the rocket's engines is off. So, we need to know the height (
) that the rocket reaches while its engine is on and we need to know the distance (
) that it travels while its engine is off.
For solving this we use the kinematic equations:
In the first part we have:

and the final speed is:

In the second part, the final speed of the first part it will be the initial speed, and the final speed is zero, since gravity slows it down the rocket.
So, we have:

The sum of these heights will give us the total height, which is known:

This is the time that its needed in order for the rocket to reach the required altitude.
Acceleration is the rate of
change of the velocity of an object that is moving. This value is a result of
all the forces that is acting on an object which is described by Newton's
second law of motion. <span>Calculation of such is
straightforward, if we are given the final velocity, the initial velocity and
the total time interval. We can just use the kinematic equations. Fortunately, we are given these values. So, we calculate as follows:
</span>
acceleration = v - v0 / t
acceleration = (80 mph - 50 mph) ( 1 h / 3600) / 5 s
acceleration = 1.67 x 10^-3 m / s^2
Therefore, the acceleration of the car is 1.67 x 10^-3 m / s.
Answer:
Gate control theory of pain
Explanation:
The gate control theory of pain sates that non-painful input closes the nerve gates to painful input, which prevents pain sensation from traveling to the central nervous system (brain).
Therefore, the idea that large fibers in the sensory nerves can prevent impulses from reaching the brain and thus prevent the sensation of pain is part of the gate control theory of pain.
Answer:
The electric field at x = 3L is 166.67 N/C
Solution:
As per the question:
The uniform line charge density on the x-axis for x, 0< x< L is 
Total charge, Q = 7 nC = 
At x = 2L,
Electric field, 
Coulomb constant, K = 
Now, we know that:

Also the line charge density:

Thus
Q = 
Now, for small element:


Integrating both the sides from x = L to x = 2L

![\vec{E_{2L}} = K\lambda[\frac{- 1}{x}]_{L}^{2L}] = K\frac{Q}{L}[frac{1}{2L}]](https://tex.z-dn.net/?f=%5Cvec%7BE_%7B2L%7D%7D%20%3D%20K%5Clambda%5B%5Cfrac%7B-%201%7D%7Bx%7D%5D_%7BL%7D%5E%7B2L%7D%5D%20%3D%20K%5Cfrac%7BQ%7D%7BL%7D%5Bfrac%7B1%7D%7B2L%7D%5D)
![\vec{E_{2L}} = (9\times 10^{9})\frac{7\times 10^{- 9}}{L}[frac{1}{2L}] = \frac{63}{L^{2}}](https://tex.z-dn.net/?f=%5Cvec%7BE_%7B2L%7D%7D%20%3D%20%289%5Ctimes%2010%5E%7B9%7D%29%5Cfrac%7B7%5Ctimes%2010%5E%7B-%209%7D%7D%7BL%7D%5Bfrac%7B1%7D%7B2L%7D%5D%20%3D%20%5Cfrac%7B63%7D%7BL%5E%7B2%7D%7D)
Similarly,
For the field in between the range 2L< x < 3L:

![\vec{E} = K\lambda[\frac{- 1}{x}]_{2L}^{3L}] = K\frac{Q}{L}[frac{1}{6L}]](https://tex.z-dn.net/?f=%5Cvec%7BE%7D%20%3D%20K%5Clambda%5B%5Cfrac%7B-%201%7D%7Bx%7D%5D_%7B2L%7D%5E%7B3L%7D%5D%20%3D%20K%5Cfrac%7BQ%7D%7BL%7D%5Bfrac%7B1%7D%7B6L%7D%5D)
![\vec{E} = (9\times 10^{9})\frac{7\times 10^{- 9}}{L}[frac{1}{6L}] = \frac{63}{6L^{2}}](https://tex.z-dn.net/?f=%5Cvec%7BE%7D%20%3D%20%289%5Ctimes%2010%5E%7B9%7D%29%5Cfrac%7B7%5Ctimes%2010%5E%7B-%209%7D%7D%7BL%7D%5Bfrac%7B1%7D%7B6L%7D%5D%20%3D%20%5Cfrac%7B63%7D%7B6L%5E%7B2%7D%7D)
Now,
If at x = 2L,

Then at x = 3L:

Answer:
Part a)
f = 371.1 Hz
Part b)
f = 417.7 Hz
Part c)
beat frequency = 46.6 Hz
Explanation:
Part a)
Due to doppler's Effect the frequency of the sound heard by the train which is moving away from the observer is given as



Part b)
Now from the second train which is approaching the person we can say



Part c)
As we know that beat frequency is the difference in the frequency from two sources

