Answer: Her velocity magnitude (v) relative to the shore is 5.70 km/h.
Explanation:
Let Q be the speed of the boat, and P be the speed of the river flow.
R represents the resultant velocity combining boat velocity and river current.
According to vector addition using the law of triangles:

From the diagram:
P = 3.5 km/h, Q = 4.5 km/h




Therefore, her velocity magnitude relative to the shore is 5.70 km/h.
Answer:
0.018 J
Explanation:
The work required to bring the charge from infinity to the point P is equal to the change in its electric potential energy. This can be expressed as

where
represents the charge's magnitude
and
signifies the potential difference between point P and infinity.
After substituting into the formula, we arrive at

Power is defined as the speed at which work is performed on an object. Like all rates, power is measured in relation to time. It reflects how quickly a task is completed. Two identical tasks can be executed at varying speeds - one slower and the other faster. The equation P = Fv can be used, where P symbolizes power, F denotes force, and V represents average velocity. Calculating the average velocity gives us V = P/F, or V = (5.8 x 10^4 W) / (2.1 x 10^4 N), resulting in V = 2.8 m/s.
The overall force acting on the vehicle is zero
Explanation:
Let's evaluate the situation separately for the vertical direction and the horizontal direction along the slope.
Considering the direction perpendicular to the slope, two forces are in effect:
- The weight component acting perpendicular to the slope,
, directed into the slope - The normal force N, directed outward from the slope
Equilibrium exists here, indicating the net force in this direction is zero.
Now let’s examine the parallel direction to the slope. We have two forces present:
- The weight component aligned with the slope,
, directed down the slope - The frictional force
, acting up the slope
The car moves at a constant speed in this direction, indicating that its acceleration is zero.

Thus, according to Newton's second law,

implying the net force is zero:

Learn more about slopes and friction: