Answer:
The mass of the skateboard is 1.25 kg.
Explanation:
We have,
Mass of dog, m = 5 kg
Initial speed of dog, u = 2.5 m/s
Initial speed of skateboard, u' = 0 (at rest)
The dog jumps onto the skateboard and both the dog and skateboard move with a speed of 2.00 m/s. It is the common speed of the dog +skateboard, V = 2 m/s. We need to find the mass of the skateboard. Using conservation of momentum as :

m' is mass of skateboard

So, the mass of the skateboard is 1.25 kg.
Answer:
normal force, the pluck will move off in a different direction
Explanation:
Answer:
it points towards positive charges
The correct answer is :
According to classical electrodynamics, light energy is a wave that is absorbed by atoms in a manner similar to how an object absorbs radiant heat. So, the atoms of a metal would absorb more energy the brighter the light was. It would be feasible for an electron in a metal to break free from its atoms if it received enough energy from the incoming wave. The more energy absorbed, the more energetic the metal's released electrons would be. Additionally, no electrons could conceivably be ejected until each atom had enough light energy. Light intensity was far more important than light frequency.
In many respects, the photo-electric effect contradicted this strategy:
- If the light was below a specific frequency, no matter how bright it was, no electrons were released. Increased light intensity increased the number of electrons that were released, but not their energy, if the light was above this frequency.
- Regardless of how weak the light was, electrons were nearly immediately emitted from the metal.
- Even though the intensity of the light was reduced, an increase in its frequency led to more energising electrons leaving the metal.
To learn more about photo-electric effect refer the link:
brainly.com/question/25630303
#SPJ4