Answer:
Tt = 70 + 135e^-0.031t
13 minutes
Explanation:
Given that :
Initial temperature, Ti = 205°
Temperature after 2.5 minutes = 195°
Temperature of room, Ts= 70
Using the relation :
Tt = Ts + Ce^-kt
Temperature after time, t
When freshly poured, t = 0
205 = 70 + Ce^-0k
205 = 70 + C
C = 205 - 70 = 135°
T after 2.5 minutes to find proportionality constant, k
Tt = Ts + Ce^-kt
195 = 70 + 135e^-2.5k
125 = 135e^-2.5k
125 / 135 = e^-2.5k
0.9259 = e^-2.5k
Take In of both sides :
−0.076989 = - 2.5k
k = −0.076989 / - 2.5
k = 0.031
Equation becomes :
Tt = 70 + 135e^-0.031t
t when Tt = 160
160 = 70 + 135e^-0.031k
90 = 135e^-0.031t
90/135 = e^-0.031t
0.6667 = e^-0.031t
In(0.6667) = - 0.031t
−0.405465 = - 0.031t
t = 0.405465/ 0.031
t = 13.071
t = 13 minutes
Answer:
F = m a = m v / t where v is the change in velocity in time t
F = p / t since m v is equal to p
F = 2.2 (kg m / s) / 1.1 s = 2 kg-m / s^2 = 2 N
Or you can use the impulse equation
The frequency of this wave is 3
Answer:
A) The net force
Explanation:
If two forces of equal strength act on an object in opposite directions, the forces will cancel, resulting in a net force of zero and no movement.
You could answer this right away IF you knew the length of each wave, right ?
Well, Wavelength = (speed) / (frequency).
Speed = 3 x 10⁸ m/s (the speed of light)
and
Frequency = 90.9 x 10⁶ Hertz.
So the length of each wave is 3 x 10⁸ / 90.9 x 10⁶ meters.
To answer the question, see how many pieces you have to cut
that 1.5 km into, in order for each piece to be 1 wavelength.
It'll be
(1,500 meters) divided by (3 x 10⁸ meters/sec) / (90.9 x 10⁶ Hz)
To divide by a fraction, flip the fraction and then multiply:
(1500 meters) times (90.9 x 10⁶ Hz)/(3 x 10⁸ meters/sec)
= 454.5