First, let us calculate the total distance that each have
taken after 2 hours.
Let’s say that:
A = sailboat which sails at 23 mph in a direction 330°
B = sailboat which sails at 34 mph in a direction 190°
Calculating for distances:
dA = 23 mph (2 hours) = 46 miles
dB = 34 mph (2 hours) = 68 miles
Imagining a Cartesian coordinate, the angle θ
between the two sailboats is simply the difference:
θ = 330°
- 190°
θ = 140°
We know that from the law of cosines:
c^2 = a^2 + b^2 – 2 a*b*cos θ
Therefore the
distance between the two after 2 hours, C, is:
C^2 = 46^2 +
68^2 – 2 (46) (68) cos(140)
<span>C = 107.39 miles</span>
Answer:
The true statements are;
a.The decrease in the amplitude of an oscillation caused by dissipative forces is called damping
b.An oscillation that is maintained by a driving force is called forced oscillation
Explanation:
To answer the question, we analyze each of the options as follows;
a.The decrease in the amplitude of an oscillation caused by dissipative forces is called damping.
The above statement is true as damped oscillation is one in which the amplitude is decreased by dissipative forces
b.An oscillation that is maintained by a driving force is called forced oscillation.
When a damped oscillator is allowed to oscillate by itself, it will stop eventually. However when a force is applied to maintain the oscillation the oscillation is then known as a forced oscillation
The above statement is true
c.In a mechanical system, the amplitude of an oscillation diminishes with time unless the lost mechanical energy is replaced.
The above statement is only true in damped oscillation system
d.The increase in amplitude of an oscillation by a driving force is called forced oscillation.
Forced oscillation, as described above, is one the maintains the oscillation of damped oscillator, therefore, the above statement is not correct.
Answer:1.- b. Change in color.
It's change in color because the other can happen by via a physical change.
2.- d. A metal is added to an acid and hydrogen gas is formed.
A chemical change results in change of an object chemical structure being disrupted or altered.
Explanation:
Cellular telephone service, television, garage-door openers, toy walkie-talkies, RC model airplanes and boats, taxi communication, ambulance communication, police communication, fire communication, cordless telephones, wireless headphones, 'microwave' ovens, and Bluetooth stuff, all radio waves to transmit and receive their signals.
None of these use 'microwaves' ... not even 'microwave' ovens. 'Microwave' is a label for radio at frequencies above 3 GHz, and none of these things operate at frequencies that high. Bluetooth and microwave ovens operate around 2.45 GHz.
Wi-Fi has one set of channels around 2.4 GHz ... radio waves but not microwaves. Wi-Fi also has another set of channels around 5 GHz ... radio waves that can properly also be called 'microwaves'.
Some TV remotes use infrared waves to communicate with the TV set.
We don't (yet ?) manufacture anything that uses ultraviolet rays, X-rays, or gamma rays for communication. Even if we knew how, these forms of radiation are too dangerous to go shining them around all over the place where people are.
