Answer:
trick to this answer in this question
F=-ks
F=-(390)(.45)
F=-175.5 N
Work=force x displacement
Work= 175.5(0.45)
Work= 78.98 J
Work = ∆E =78.98 J
Answer=79J (first option)
Answer:
<u>40 m/s</u>
Explanation:
The final velocity of an object that experiences a period of acceleration is given by:
v - vi = A*t
Initial velocity, vi, is = 20m/s
Acceleration, A, is 4m/2^2
Time, t, is 5 seconds
v - vi = A*t
v - 20m/s = (4m/2^2)/(5 sec)
v = (20 m/s) + (20 m/s)
v = 40 m/s
One divides the volume by the density. You get
(or one liter, if you want)
The gazelle has zero average acceleration because it's moving at a constant speed. Constant speed means no change in speed means zero acceleration.
The cheetah, on the other hand, changes its speed from 0 m/min to 1820 m/min in a matter of 3 seconds, so its average acceleration is
a[ave] = (1820 m/min - 0 m/min) / (3 s)
… = (1820 m/min) / (3/60 min)
… = 36,400 m/min²
… = (36,400 m) / (60 s)²
… = 91/9 m/s² ≈ 10.1 m/s²
