The correct answer for the given question above would be option C. RADIOACTIVE DATING. The one that provides evidence that has helped earth scientists determine the age of the earth more precisely is radioactive dating. Radioactive dating<span> is a method of </span>dating<span> rocks and minerals using </span>radioactive <span>isotopes. Hope this answer helps. </span>
Answer:
Net force= 14 units
The object is unbalanced
Explanation:
The net force refers to the sum of all forces applied to an object. However, the direction of force applied determine the net force. In this question, a boy and girl is pulling a heavy crate at the same time.
This means that the force is in the same direction, hence, the net force will be:
F(N) = 7 + 7 = 14 unit
However, since the pull is occuring at the same direction. This means that the object has a net force, therefore, will move in a particular direction. This means that the OBJECT IS UNBALANCED
Answer:
Explanation:
The tidal current flows to the east at 2.0 m/s and the speed of the kayaker is 3.0 m/s.
Let Vector is the tidal current velocity as shown in the diagram.
In order to travel straight across the harbor, the vector addition of both the velocities (i.e the resultant velocity, must be in the north direction.
Let is the speed of the kayaker having angle \theta measured north of east as shown in the figure.
For the resultant velocity in the north direction, the tail of the vector and head of the vector must lie on the north-south line.
Now, for this condition, from the triangle OAB
Hence, the kayaker must paddle in the direction of in the north of east direction.
Remaining Distance = 180miles-90miles= 90miles
Time taken for first part of her journey= 90miles / 30miles/h= 3hours
To have average speed of 40mph,
Let the time taken for second part be xh
180 / 3h+xh =40
3+x= 4.5h
x =1.5h
Constant speed she must drive = 90miles / 1.5h = 60mph