Answer:
2.69 m/s
Explanation:
Hi!
First lets find the position of the train as a function of time as seen by the passenger when he arrives to the train station. For this state, the train is at a position x0 given by:
x0 = (1/2)(0.42m/s^2)*(6.4s)^2 = 8.6016 m
So, the position as a function of time is:
xT(t)=(1/2)(0.42m/s^2)t^2 + x0 = (1/2)(0.42m/s^2)t^2 + 8.6016 m
Now, if the passanger is moving at a constant velocity of V, his position as a fucntion of time is given by:
xP(t)=V*t
In order for the passenger to catch the train
xP(t)=xT(t)
(1/2)(0.42m/s^2)t^2 + 8.6016 m = V*t
To solve this equation for t we make use of the quadratic formula, which has real solutions whenever its determinat is grater than zero:
0≤ b^2-4*a*c = V^2 - 4 * ((1/2)(0.42m/s^2)) * 8.6016 m =V^2 - 7.22534(m/s)^2
This equation give us the minimum velocity the passenger must have in order to catch the train:
V^2 - 7.22534(m/s)^2 = 0
V^2 = 7.22534(m/s)^2
V = 2.6879 m/s
Answer:
C
Explanation:
I think it's C, because at that point, you are going fastest. Sorry if im wrong, hope this helps.
<h2>
Answer: Heat transfer by radiation</h2>
Explanation:
There are three ways in which the thermal transfer (heat) occurs:
1. By Conduction, when the transmission is by the <u>direct contact.</u>
2. By Convection, heat transfer<u> in fluids</u> (like water or the air, for example).
3. By <u>Radiation</u>, by the electromagnetic waves (they can travel through any medium and in vacumm or empty space)
Since outter space is vacuum (sometimes called "empty"), energy cannot be transmitted by convection, nor conduction. It must be transmitted by electromagnetic waves that are able to travel with or without a medium.
