D is the correct answer. Constructive Interference occurs when the crests of one wave overlaps with the crests of another wave. The reason it is called "constructive" is because one wave is adding energy to another wave. Hope this helps!
Answer:
3. 9600m/s
4. 2.5m/s
Explanation:
To find the final velocity of the object which accelerates at 40m/s/s for four minutes, we first need to convert the 4 minutes to seconds. There are 60 seconds in a minute so 4 minutes is equal to 4x60 = 240 seconds.
To calculate the final velocity we just multiply the acceleration rate by the time, so 40x240=9,600 m/s
The final velocity of the object would be 9600m/s.
If an object's final velocity was 115m/s after 45 seconds then we need to find out how much it accelerated in that 45 seconds to find the starting velocity. 45x2.5=112.5 It increased in speed by 112.5m/s over 45 seconds, so its initial speed was 112.5m/s slower than its final speed. 115-112.5=2.5, the object's starting velocity was 2.5m/s.
Hope this helped!
The answer:
-> When the forklift raises an object, it is doing positive work. This is because electrical energy is converted in to kinetic energy that is required for the forklift to raise the object.
-> However the resultant force of the object reacts on to the forklift, causing force of drag. This slightly weighs the forklift downwards due to how much mass the object weighs.
Answer:
E) be two times larger.
Explanation:
As we know that the relation between the resistance and the resistivity of the wire is given as:
![R=\rho.\frac{l}{a}](https://tex.z-dn.net/?f=R%3D%5Crho.%5Cfrac%7Bl%7D%7Ba%7D)
where:
resistivity of the wire
length of wire
area of wire
resistance
Now, when the length of the wire is four times the initial length then for the resistance to remain constant:
![R=\rho.\frac{4l}{a'}](https://tex.z-dn.net/?f=R%3D%5Crho.%5Cfrac%7B4l%7D%7Ba%27%7D)
where:
area of the new wire
![\rho.\frac{l}{a} =\rho.\frac{4l}{a'}](https://tex.z-dn.net/?f=%5Crho.%5Cfrac%7Bl%7D%7Ba%7D%20%3D%5Crho.%5Cfrac%7B4l%7D%7Ba%27%7D)
![a'=4a](https://tex.z-dn.net/?f=a%27%3D4a)
we know that area of the cross section of wire is given as:
![a=\pi.r^2](https://tex.z-dn.net/?f=a%3D%5Cpi.r%5E2)
![\pi.r'^2=4\times \pi.r^2](https://tex.z-dn.net/?f=%5Cpi.r%27%5E2%3D4%5Ctimes%20%5Cpi.r%5E2)
![r'=2r](https://tex.z-dn.net/?f=r%27%3D2r)
Hence the radius must be twice of the initial radius for the resistance to be constant when length is taken four times.