Answer:
Kinetic energy and momentum are conserved.
Explanation:
A star is born when clouds of dust and elements are gathered together in a certain space due to gravity, more and more mass and therefore pressure builds. When the pressure becomes enough to overcome the electronic repulsive force between two hydrogen nuclei, they are forced together and massive amounts of energy are given off forming helium atoms. This energy is then used to fuse other nuclei together. This could be compared to the way human life starts, where instead of 2 nuclei joining together to start a life cycle, two gametes, or sex cells are joined together. Also at the start of both a star and persons life, we are weak and we gain strength until we reach the height of our existence, then humans slowly become less efficient at doing what they do until eventually they cannot sustain themselves any further.
The impulse required to decrease the speed of the boat is equal to the variation of momentum of the boat:

where
m=225 kg is the mass of the boat

is the variation of velocity of the boat
By substituting the numbers into the first equation, we find the impulse:

and the negative sign means the direction of the impulse is against the direction of motion of the boat.
1. 2504.63 J
2. 929.5m/s
Hope this helps :)
I can explain it as well if you’d like
Answer:
Solution:
we have given the equation of motion is x(t)=8sint [where t in seconds and x in centimeter]
Position, velocity and acceleration are all based on the equation of motion.
The equation represents the position. The first derivative gives the velocity and the 2nd derivative gives the acceleration.
x(t)=8sint
x'(t)=8cost
x"(t)=-8sint
now at time t=2pi/3,
position, x(t)=8sin(2pi/3)=4*squart(3)cm.
velocity, x'(t)=8cos(2pi/3)==4cm/s
acceleration, x"(t)==8sin(2pi/3)=-4cm/s^2
so at present the direction is in y-axis.