a) Let's call x the direction parallel to the river and y the direction perpendicular to the river.
Dave's velocity of 4.0 m/s corresponds to the velocity along y (across the river), while 6.0 m/s corresponds to the velocity of the boat along x. Therefore, the drection of Dave's boat is given by:

relative to the direction of the river.
b) The distance Dave has to travel it S=360 m, along the y direction. Since the velocity along y is constant (4.0 m/s), this is a uniform motion, so the time taken to cross the river is given by

c) The boat takes 90 s in total to cross the river. The displacement along the y-direction, during this time, is 360 m. The displacement along the x-direction is

so, Dave's landing point is 540 m downstream.
d) If there were no current, Dave would still take 90 seconds to cross the river, because its velocity on the y-axis (4.0 m/s) does not change, so the problem would be solved exactly as done at point b).
A device that detects small current differences and prevents electrocution that is often required as a safety measure for bathroom, kitchen, and exterior outlets is referred to as: Ground-fault interrupter.
<h3>What are
arc-fault circuit interrupter?</h3>
According to "Article 100 Arc-Fault Circuit interrupter (AFCI)," arc-fault circuit interrupter is an electrical device which is designed and developed to deenergize the electrical circuit whenever it detects and recognizes characteristics unique to arcing.
Similarly, a ground-fault interrupter simply refers to an electrical device that is designed and developed for the detection of small current differences in an electrical circuit.
The main purpose of a ground-fault interrupter is to prevent electrocution or electrical shock and as such, it is an important safety measure for the following areas in a building:
- Bathroom
- Kitchen
- Exterior outlets
Read more on ground-fault interrupter here: brainly.com/question/12615861
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The formula to find work is

. In this case, the force exerted on the rock is 15 Newtons and the distance the rock moved was 2 meters, so 15 * 2 = 30. The answer to your question is
D) 30 n-m.
Explanation:
In the parallel combination, the equivalent resistance is given by :

4. When three 150 ohms resistors are connected in parallel, the equivalent is given by :

5. Three resistors of 20 ohms, 40 ohms and 100 ohms are connected in parallel, So,

Hence, this is the required solution.
Answer:
159 N
Explanation:
The force of friction is a resistive force that acts against an object in motion (or on the verge of moving).
There are two types of force of friction:
- Force of static friction: it occurs when the object is still at rest
- Force of kinetic friction: it occurs when the object is sliding on a surface and it is in motion
In this problem, we are in the 2nd situation, so we want to calculate the force of kinetic friction.
This force is given by:

where
is the coefficient of kinetic friction
N is the normal force exerted on the object
For the sled and the girl in this problem,
is the coefficient of kinetic friction
N = 636 N is the normal force
So the force of friction is
