Answer:
4.0 m/s
Explanation:
The motion of the diver is the motion of a projectile: so we need to find the horizontal and the vertical component of the initial velocity.
Let's consider the horizontal motion first. This motion occurs with constant speed, so the distance covered in a time t is

where here we have
d = 3.0 m is the horizontal distance covered
vx is the horizontal velocity
t = 1.3 s is the duration of the fall
Solving for vx,

Now let's consider the vertical motion: this is an accelerated motion with constant acceleration g=9.8 m/s^2 towards the ground. The vertical position at time t is given by

where
h = 4.0 m is the initial height
vy is the initial vertical velocity
We know that at t = 1.3 s, the vertical position is zero: y = 0. Substituting these numbers, we can find vy

So now we can find the magnitude of the initial velocity:

The answer is 15 kilometers in 20 minutes.
Answer:
Higher mass or higher speed
Explanation:
Higher mass will require more force
F= ma if m goes up F goes up to stop in the same distance
Answer: The option (C) is correct. The energy travels horizontally.
Explanation: When the pebble is thrown into a calm lake, there will be disturbance in the lake. The ripples are formed from the center and move outward because the energy is carried out from particle to particle.
The distribution of the energy among the particles starts from center and it will carry out outward. This disturbance will occur horizontally.
Therefore, the energy travels horizontally.