<span>The momentum before the collision is equal to the momentum after the collision</span>
Answer:
324 people
Explanation:
radius r = diameter / 2 = 45cm /2 = 22.5 cm or 0.225 m
We can calculate the total volume of the log by computing the volume of each cylindrical log:
So the total volume of all 12 logs is
The weight that the raft can support, is the buoyancy force subtracted by its own weight.
The buoyancy force is basically the weight of the water is displaced, which is water density times volume. The log weight is also log density times its volume
where 
are the density of water and raft, respectively. But since we have the specific gravity of wood is 0.6. That measn
Therefore 
Let g = 9.8m/s2. We can now calculate the force that the raft can support
Each person has a mass of 68kg, their weight would be
W = 68*g = 68*9.8 = 666.4N
So the maximum number of people that the raft can hold is
F / W = 216129.2 / 666.4 = 324 people
Answer:
Explanation:
3. The word circuit means "go around", therefore a circuit is a pathway or closed path around which electricity (or water) flows.
4. Electrons flowing through a wire can be compared to water flowing through a hose. Once the flow of electrons or water is going, work, is performed.
5. You would get shocked in a bumper car by touching the floor and the ceiling at the same time. This means you are completing the circuit allowing electricity to flow.
6. Electricity from a wall outlet has enough energy to stop your
heart.
7. Electricity is the flow of electrons, because electrons move or jump from atom to atom.
8. Materials that allow electrons to move easily from atom to atom are called conductors.
9. Materials that do not allow electrons to flow easily are called insulators.
10. Semi- conductors are materials that are somewhere in between
.
11. Voltage is the force or pressure of electricity and is compared to the amount of water pressure in a hose.
12. Current (amps
) is the amount of electricity and is compared to the amount of water in a hose
.
13. Watts (power) is the term for work performed by electricity.
Answer:
No,
Explanation:
An electromagnetic wave is made of vibrating electric and magnetic fields that continually induce each other; matter is not needed for this to occur.
<h3>
Answer: 130 newtons</h3>
===============================================================
Explanation:
We'll need the acceleration first.
- The initial speed (let's call that Vi) is 8.0 m/s
- The final speed (Vf) is 0 m/s since Sam comes to a complete stop at the end.
- This happens over a duration of t = 4.0 seconds
The acceleration is equal to the change in speed over change in time
a = acceleration
a = (change in speed)/(change in time)
a = (Vf - Vi)/(4 seconds)
a = (0 - 8.0)/4
a = -8/4
a = -2
The acceleration is -2 m/s^2, meaning that Sam slows down by 2 m/s every second. Negative accelerations are often associated with slowing down. The term "deceleration" can be used here.
Here's a further break down of Sam's speeds at the four points of interest
- At 0 seconds, he's going 8 m/s
- At the 1 second mark, he's slowing down to 8-2 = 6 m/s
- At the 2 second mark, he's now at 6-2 = 4 m/s
- At the 3 second mark, he's at 4-2 = 2 m/s
- Finally, at the 4 second mark, he's at 2-2 = 0 m/s
Next, we'll apply Newton's Second Law of motion
F = m*a
where,
- F = force applied
- m = mass
- a = acceleration
We just found the acceleration, and the mass is fairly easy as all we need to do is add Sam's mass with the sled's mass to get 60+5.0 = 65 kg
So the force applied must be:
F = m*a
F = 65*(-2)
F = -130 newtons
This force is negative to indicate it's pushing against the sled's momentum to slow Sam down.
The magnitude of this force is |F| = |-130| = 130 newtons
