Answer:
1) from the positive x-axis.
2)
Explanation:
Given:
speed of rowing in still water,
1)
speed of water stream,
we know that the direction of resultant of the two vectors is given by:
where:
the angle of resultant vector from the positive x-axis.
angle between the given vectors
When the rower wants to reach at the opposite end then:
so,
from the positive x-axis.
2)
Now the resultant velocity of rowing in the stream:
Therefore time taken to cross a 4 miles wide river:
It will be unbalanced and at terminal velocity
Now
Option b is correct
Answer:
b a model of water temperatures in the oceans
Explanation:
A conceptual model is a means of representing abstract theories, with the aim of helping the audience form mental pictures about the subject being discussed. Most of these models utilize diagrams to help form a better understanding of the subject.
In geothermal explorations, water temperatures can be represented using plane or cross sectional views to demonstrate the varying temperatures of water. This is a useful guidde in the exploration proceess and helps any who read the illustrations to form a better understanding of the process and conditions.
The correct answer to the question is by increasing their masses, or by decreasing the separation distance between them.
EXPLANATION:
Let us consider two bodies having masses M and M' respectively . The two bodies are separated from their centre of masses by a distance of R.
As per Newton's law of gravitation, the two bodies will exert gravitational force on one another. The gravitational force produced between them is calculated as -
Gravitational force
Here, G is the gravitational force constant.
From above, we see that the gravitational force is directly proportional to the product of masses of two bodies and inversely proportional to the square of separation distance between them.
Hence, the gravitational force between two objects can be increased by increasing their masses, or by decreasing the distance between them.