Answer:
t = 4.17 [s]
Explanation:
We know that work is defined as the product of force by distance.
W = F*d
where:
F = force [N] (units of Newtons)
d = distance = 6.34 x 10⁴ [mm] = 63.4 [m]
In order to find the force, we must determine the weight of the box, the weight can be determined by means of the product of mass by gravitational acceleration.
w = m*g
where:
m = mass = 1.47 x 10⁴ [g] = 14.7 [kg]
g = gravity acceleration = 9.81 [m/s²]
w = 14.7*9.81
w = 144.2 [N]
Therefore the work can be calculated.
W = w*d
W = 144.2*63.4
W = 9142.72 [J] (units of Joules)
Power is now defined in physics as the relationship of work at a given time
P = W/t
where:
P = power = 2190 [W]
t = time [s]
Now clearing t, we have.
t = W/P
t = 9142.72/2190
t = 4.17 [s]
The braking force is -400 N
Explanation:
We can solve this problem by using the impulse theorem, which states that the impulse applied on the ferry (the product of force and time) is equal to its change in momentum:
where in this problem, we have:
F is the force applied by the brakes
is the time interval
m = 13,000 kg is the mass of the ferry
u = 2.0 m/s is the initial velocity
v = 0 is the final velocity
And solving for F, we find the force applied by the brakes:
where the negative sign indicates that the direction is backward.
Learn more about impulse:
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Answer:
<u>Informed Consent- The study didn't conform this ethical standard.</u>
<u>Debriefing- The study conforms this ethical standard.</u>
<u>Confidentiality- The study conforms this ethical standard.</u>
<u>Protection from harm- The study conforms this ethical standard.</u>
Explanation:
<u>Informed consent</u> is described as a procedure whereby researchers tend to provide details about specific research they are going to conduct, the risk & benefits involved in the study, different alternatives involved in the procedure, etc.
<u>Debriefing </u>is described as a process that is being conducted in any of the different psychological research encompassing human participants after specific research is completed. The researcher tends to describe the details of the research to the participants.
<u>Confidentiality</u> is described as one of the different code of ethics followed by health workers or psychologists. While practicing confidentiality, a psychologist tends to promise his or her participants that he or she will keep everything a secret whatever is being discussed or shared between both of them.
<u>Protection from harm</u> determines that the psychologists conducting research follows the ethics in which he or she has to protect all the participants from any kind of harm.
Assuming 280 miles is the total distance travelled:
Let b = boat speed in still water
Let c = current speed.
For the downstream trip the speed is b + c. In 7 hours at the speed of (b + c) mph the boat travels 140 miles.
7(b + c) = 140 .............(1)
For the upstream trip the speed is b - c. In 14 hours at the speed of (b - c) mph the boat travels 140 miles.
14(b - c) = 140 ............(2)
The left hand sides of equations (1) and (2) are equal. Therefore we can write
7b + 7c = 14b - 14c ...........(3)
Rearranging equation (3) we get
21c = 7b
c = b/3 .......................(4)
The value for c obtained in equation (4) should now be substituted into equation (1) which can then be solved to find the value of b.
B
Think of inertia of getting into a car accident without a seat belt although the car stops you will not you would likely fly out the window
