Answer:
Explanation:
Recall the formula for acceleration:
, where 
is final velocity, 
is initial velocity, and 
is elapsed time (change in velocity over this amount of time).
Let's look at our time vs velocity graph. At t=0 seconds, V=25 m/s. So her initial velocity is 25 m/s.
We want to find the acceleration during the first 5 seconds of motion. Well, looking at our graph, at t=5 seconds, isn't our velocity still 25 m/s? Therefore, final velocity is 25 m/s (for this period of 5 seconds).
We are only looking from t=0 seconds to t=5 seconds which is a total period of 5 seconds. Therefore, elapsed time is 5 seconds.
Substituting values in our formula, we have:
Alternative:
Without even worrying about plugging in numbers, let's think about what acceleration actually is! Acceleration is the change in velocity over a certain period of time. If we are not changing our velocity at all, we aren't accelerating! In the graph, we can see that we have a straight line from t=0 seconds to t=5 seconds, the interval we are worried about. This indicates that our velocity is staying the same! At t=0 seconds, we have a velocity of 25 m/s and that velocity stays the same until t=5 seconds. Even though we are moving, we haven't changed velocity, which means our average acceleration is zero!
Answer:
The semi truck travels at an initial speed of 69.545 meters per second downwards.
Explanation:
In this exercise we see a case of an entirely inellastic collision between the semi truck and the car, which can be described by the following equation derived from Principle of Linear Momentum Conservation: (We assume that velocity oriented northwards is positive)
(1)
Where:
, 
- Masses of the semi truck and the car, measured in kilograms.
, 
- Initial velocities of the semi truck and the car, measured in meters per second.
- Final speed of the system after collision, measured in meters per second.
If we know that 
, 
, 
and 
, then the initial velocity of the semi truck is:
The semi truck travels at an initial speed of 69.545 meters per second downwards.
It becomes a different element
<h2>Answer:</h2>
<u>Distance covered is 6.9 meters</u>
<h2>Explanation:</h2>
Data given:
Work Done = 345 kJ = 345000 J
Force = 5 x 10 ^ 4 = 50000 N
Distance = ?
Solution:
As we know that
Work Done = Force applied x Distance covered
By arranging the equation we get
Work / Force = Distance covered
By putting the values
345000 / 50000 = 6.9
So distance covered is 6.9 meters
I think your question should be:
An industrial laser is used to burn a hole through a piece of metal. The average intensity of the light is
What is the rms value of (a) the electric field and
(b) the magnetic field in the electromagnetic wave emitted by the laser
Answer:
a) 
b) 
Explanation:
To find the RMS value of the electric field, let's use the formula:
Where
;
;
Therefore
![E_r_m_s = sqrt*{(1.239*10^9W/m^2) / [(3.00*10^8m/s)*(8.85*10^-^1^2C^2/N.m^2)]}](https://tex.z-dn.net/?f=%20E_r_m_s%20%3D%20sqrt%2A%7B%281.239%2A10%5E9W%2Fm%5E2%29%20%2F%20%5B%283.00%2A10%5E8m%2Fs%29%2A%288.85%2A10%5E-%5E1%5E2C%5E2%2FN.m%5E2%29%5D%7D%20)
b) to find the magnetic field in the electromagnetic wave emitted by the laser we use:
;
;
