Answer:

Explanation:
When a standing wave is formed with six loops means the normal mode of the wave is n=6, the frequency of the normal mode is given by the expression:

Where
is the length of the string and
the velocity of propagation. Use this expression to find the value of
.

The velocity of propagation is given by the expression:

Where
is the desirable variable of the problem, the linear mass density, and
is the tension of the cord. The tension is equal to the weight of the mass hanging from the cord:

With the value of the tension and the velocity you can find the mass density:


1. 2+0.5+2.5= 3. 2km/hr average
2. 14-6=4seconds. 8m/s in 4s = 2m/s acceleration
3. 15m/s divided by 2.5 = 6m/s acceleration
Answer:
It takes 77 N
Explanation:
Using Newton's second law of motion, F=ma (Force equals mass times acceleration. Since the mass of the couch is 385 kg and the target acceleration is 0.2 m/s, you simply multiply mass times acceleration (ma) to get the total force, or 77 N.
Answer:
A)
B)
Explanation:
Given that
Force = F
Increase in Kinetic energy = 

we know that
Work done by all the forces =change in the kinetic energy
a)
Lets distance = d
We know work done by force F
W= F .d
F.d=ΔKE


b)
If the force become twice
F' = 2 F
F'.d=ΔKE'
2 F .d = ΔKE' ( F.d =Δ KE)
2ΔKE = ΔKE'

Therefore the final kinetic energy will become the twice if the force become twice.