Answer:
The question is incomplete. However, I believe, it is asking for the acceleration of the elevator. This is 3.16 m/s².
Explanation:
By Hooke's law, 
F is the force on a spring, k is the spring constant and e is the extension or compression.
From the question,

This is the force on the mass suspended on the spring. Its acceleration, a, is given by



This acceleration is more than the acceleration due to gravity, g = 9.8 m/s². Hence the elevator must be moving up with an acceleration of
12.96 - 9.8 m/s² = 3.16 m/s²
Answer:
B. 47-54 miles/hour
Explanation:
Gale is a strong wind which is depicted by red warning flag. According to U.S. National Weather Service gale is a sustained surface wind. It is also used to refer winds from tropical coastal areas.
On the basis of force of wind gale is divided in four groups:
- Near gale - 32-38 mph
- Gale - 39-46 mph
- Strong gale - 47-54 mph
- Storm - 55-63 mph
Newwton's law of inertia states that an object will not be able to move unless force is applied to it
Answer:
Solution given:
No of waves[N] =20crests & 20 troughs
=20waves
Time[T]=4seconds
distance[d]=3cm=0.03m
Now
<u>Wave</u><u> </u><u>length</u><u>=</u>3cm=3 × 
<u>Frequency</u>=
=
=5Hertz
and
Wave speed:wave length×frequency=3 ×
×5=1.5 ×
.