The correct answer is c) gas.
In gases, in fact, particles are not bound together (and the intermolecular forces between them are negligible) and they are completely free to move. For this reason, when a gas is put in a container, the particles of the gas will move in every possible direction, filling all the space available in the container (for this reason, we also say that gases have no fixed shape).
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).
Answer:
Time, t = 10 seconds
Explanation:
Given the following data;
Mass = 10kg
Force = 10N
Final velocity = 10m/s
Initial velocity = 0m/s
To find the time;
First of all, we would find the acceleration of the box.
Force = mass * acceleration
10 = 10 * acceleration
Acceleration = 10/10 = 1m/s²
Now, we can find the time by using the first equation of motion;
V = U + at
10 = 0 + 1t
10 = t
Time, t = 10 seconds
Therefore, it will take 10 seconds for the box to come to a complete stop.
Answer:
1)every planet move in elliptical path.