Answer:
Both of them reach the lake at the same time.
Explanation:
We have equation of motion s = ut + 0.5at²
Vertical motion of James : -
Initial velocity, u = 0 m/s
Acceleration, a = g
Displacement, s = h
Substituting,
s = ut + 0.5 at²
h = 0 x t + 0.5 x g x t²

Vertical motion of John : -
Initial velocity, u = 0 m/s
Acceleration, a = g
Displacement, s = h
Substituting,
s = ut + 0.5 at²
h = 0 x t + 0.5 x g x t²

So both times are same.
Both of them reach the lake at the same time.
If the light from the sun has higher frequencies from one side of the sun than from the other side, it is proof that the Sun is rotating.
Doppler effect states that, if a person is standing still and a source ( sound / light ) is moving towards him, the frequency of the wave emitted from the object will increase and if the source ( sound / light ) is away from him, the frequency of the wave emitted from the object will decrease.
So, if the light from the sun has higher frequencies from one side of the sun than from the other side, it means that the Sun is rotating. The higher frequencies points are the points that rotating towards Earth and lower frequencies points are the points that rotating away from Earth.
Therefore, if the light from the sun has higher frequencies from one side of the sun than from the other side, it is proof that the Sun is rotating.
To know more about Doppler Effect
brainly.com/question/15318474
#SPJ1
Answer:
This question is incomplete, a possible question would be to calculate the work done by the ball.
Work done = 8J
Explanation:
Work done by an object is calculated my multiplying the force by the distance.
The weight of this ball is 2.0N, which also represents the force exerted by the ball. The ball travels through a distance of 4m
Hence, work done = F × d
Work done = 2N × 4m
Work done = 8Nm or 8J