Since they are rowing against the current, their velocity realtive to the groud is 20-1.5 = 18.5km/h
So the distance travelled is 18.5km/h*0.5h = 9.25km
Going back with the current their ground realative velocity is 20+1.5 = 21.5km/h so the time it takes them to return 9.25 km is 9.25km/(21.5km/h) = 0.43h ~= 26 min
Here is your answer:
First find the notations:
5.0×10^2=500.
1.0×10^3=1,000
Then you multiply:
1,000×500=500,000
Your answer is...
=500,000 or 5.0×10^4
Wind is primarily driven by differences in air pressure. These variations in air pressure are due to temperature differences caused by variations in solar energy received at the surface of the Earth.
Answer:
k = 22.05 N/m
Explanation:
The potential energy of the mass is converted into potential energy of the spring.
Given:
mass m = 0.27 kg
gravitational constant g = 9.8 m/s²
distance falling/ stretching of spring h = 0.24 m

Solving for k:

We want to study the impact of a sledgehammer and a wall.
Before the sledgehammer hits the wall, it has a given velocity and a given mass, so it has momentum and it has kinetic energy.
When it hits the wall, the velocity of the hammer disappears, this means that the energy is transferred to the wall, this "transfer of energy" can be thought of a force applied for a really short time on the wall, which for the third law of Newton, the force is also applied on the hammer.
This is why you feel the impact on the handle when you hit something with a hammer, this also means that some of the energy is dissipated on your arms.
Now, because the wall is made of a material usually not as strong as the head of the sledgehammer, we will see that in this interaction the wall seems more affected than the hammer, but the forces that each one experiences are exactly equal in magnitude.
If you want to learn more, you can read:
brainly.com/question/13952508