The climate<span> was generally warmer and more humid than today, probably because of very active volcanism associated with unusually high rates of seafloor spreading.
</span><span>The first placental mammals appeared at the beginning of the Cretaceous. The Cretaceous saw the rise and extinction of the toothed birds, Hesperornis and Ichthyornis. The earliest fossils of birds resembling loons, grebes, cormorants, pelicans, flamingos, ibises, rails, and sandpipers were from the Cretaceous.</span>
Answer:
<em>The second option has a lower power output. P=30 W</em>
Explanation:
<u>Mechanical Power
</u>
It is a physical magnitude that measures the rate a work W is done over time t.

Since W=F.d

The first option means the worker will lift the box by a distance of 1.2 meters in 3 seconds by applying 250 N of force. That produces a power of

The second option requires the worker applies 75 N of force and travel a distance of 4 meters for 10 seconds, thus the power is

The second option has a lower power output
Answer:
The final velocity of the second car is 57 m/s south.
Explanation:
This is an elastic collision between two train cars. In this case, the total kinetic energy between the two bodies will remain the same.
The formula to apply is :

where ;

Given in the question that;

Apply the formula as;

{14650*18}+{3825*11} = {14650 *6} + {3825 * v₂f}
263700+42075=87900 + 3825v₂f
305775 =87900 + 3825v₂f
305775-87900 = 3825v₂f
217875=3825v₂f
217875/3825 =v₂f
56.96 = v₂f
<u>57 m/s = v₂f { nearest whole number}</u>
It must be a virtual image, because this is the only kind of image it can produce.
Answer:
-2.478
0.379
11.14
24.78
Explanation:
Angular frequency of spring in harmonic motion is given by?
ω = √(k/m)
ω = √(10/2.2)
ω = √4.54
ω = 2.13 s^-1
If at t=0 the mass is in negative amplitude (x = -A = -2.48 m) then we describe the position with negative cosine
x(t) = -A * cos(ωt)
x(t) = -2.48 * cos(2.13 * 1)
x(t) = -2.48 * 0.9993
x(t) = -2.478
Velocity and acceleration are 1st and 2nd derivative of position
b)
v(t) = Aω * sin(ωt)
v(t) = 2.48 * 2.13 * sin(2.13 * 1)
v(t) = 5.282 * sin2.13
v(t) = 5.282 * 0.03717
v(t) = 0.379 m/s
c)
a(t) = Aω^2 * cos(ωt)
a(t) = 2.48 * 2.12² * cos(2.13 * 1)
a(t) = 2.48 * 4.494 * cos2.13
a(t) = 11.15 * 0.9993
a(t) = 11.14 m/s²
d)
F = -k * x(t)
F = -10 * -2.478
F = 24.78 N