Answer:
The mass has likely lost some of its mechanical energy to resistance on its path.
Explanation:
The mechanical energy of an object is the sum of its kinetic and potential energies (KE and PE.) Ideally, the mechanical energy of a simply pendulum should be "conserved." In other words, the sum of the kinetic and potential energy of the simply pendulum should stays the same as it travels along its path.
Indeed, as the pendulum travels, some of its PE will convert to KE and back. However, the sum of these two energies is supposed to stay the same.
- When the pendulum moves from the highest point to the bottom of the path, some of its PE converts to KE. (The pendulum speeds up in this process.)
- When the pendulum moves from the bottom of its path to the opposite side, its KE is converted back to PE. (The pendulum slows down as it moves towards the other side of the path.)
However, in practice, the mechanical energy of pendulums isn't always conserved. For example, various kinds of resistances (such as air resistance) act on the pendulum as it moves. That would slow down the pendulum. Some of the pendulum's energies would be converted to heat and is lost to the surroundings.
In effect, the mechanical energy of the pendulum would become smaller and smaller over time. When the pendulum travels back towards the girl, its potential energy would be smaller than the initial value when at the girl's chin.
Answer:
20 [N], in the opposite direction of the first force.
Explanation:
We know that newton's second law stipulates that the sum of forces on a body must be equal to the product of mass by acceleration.
![SumF = m*a\\30 + F = 2*5\\F = 30 - (2*5)\\F = - 20 [N]](https://tex.z-dn.net/?f=SumF%20%3D%20m%2Aa%5C%5C30%20%2B%20F%20%3D%202%2A5%5C%5CF%20%3D%2030%20-%20%282%2A5%29%5C%5CF%20%3D%20-%2020%20%5BN%5D)
The negative sign means that the other force acting on the body must be in the opposite direction to the force of 30 [N]
Answer:
8.1 N/49 N=0.1653 which means 16.53% of the weight of the object on Earth.
Explanation:
On the Moon, where the gravitational constant is 1.62
, the weight of the 5 kg object will be: 
Where the answer is in Newtons (N) since all quantities are given in the SI system.
On Earth, on the other hand, the weight of the object is:

Therefore the object's weight on the Moon compared to that on Earth will be:

That is, 16.53% of the weight the object has on Earth.
Answer:
They collide, couple together, and roll away in the direction that <u>the 2m/s car was rolling in.</u>
Explanation:
We should start off with stating that the conservation of momentum is used here.
Momentum = mass * speed
Since, mass of both freight cars is the same, the speed determines which has more momentum.
Thus, the momentum of the 2 m/s freight car is twice that of the 1 m/s freight car.
The final speed is calculated as below:
mass * (velocity of first freight car) + mass * (velocity of second freight car) = (mass of both freight cars) * final velocity
(m * V1) + (m * V2) = (2m * V)
Let's substitute the velocities 1m/s for the first car, and - 2m/s for the second. (since the second is opposite in direction)
We get:

solving this we get:
V = - 0.5 m/s
Thus we can see that both cars will roll away in the direction that the 2 m/s car was going in. (because of the negative sign in the answer)