Answer:
C. She should get the Earth spinning on its axis again.
Explanation:
The Earth experiences day and night because of its spinning on its own axis.
If Kara's science-fiction story doesn't have the Earth spinning on its own axis, then the Earth will not experience day and night and hence Kara should incorporate this idea into his story.
The average velocity of Sandy is given by the total distance covered S divided by the total time taken t:

The total distance covered is

while the total time taken is 2 hours + half an hour (for the rest) + 1 hour and half, so

Therefore, the average velocity is
Answer:
1.73 seconds
Explanation:
The velocity the ball first hits the ground with is:
v² = v₀² + 2aΔx
v² = (0 m/s)² + 2 (-10 m/s²) (-20 m)
v = -20 m/s
The velocity it rebounds with is 3/4 of that in the opposite direction, or 15 m/s.
The time it takes to return to the ground is:
Δx = v₀ t + ½ at²
0 = (15 m/s) t + ½ (-10 m/s²) t²
0 = t (15 − 5t²)
t = √3
t ≈ 1.73 seconds
Answer:
The force is 7.8 N.
Explanation:
Given that,
Mass of small object = 2M
Mass of large object = 4M
Here, M = 1.0 kg
Force of the small block = 5.2 N
We need to calculate the acceleration of 4 kg block
Using formula of force




The 2 kg block is also accelerating at 1.3 m/s², making a total of 6 kg.
We need to calculate the force
Using formula of force

Put the value into the formula


Hence, The force is 7.8 N.
Answer:
Kinetic Energy at bottom=2886.5J (when g=9.8m/s²)
<em><u>OR</u></em>
2925J (if g=10m/s²)