Answer:
A. The closest point in the Moon's orbit to Earth
Explanation:
The perigee is defined as the closest point in the orbit of an object (such as a satellite) from the centre of the Earth. In this case, the Earth's satellite is the Moon, so the perigee is defined as the closest point in the Moon's orbit to Earth. so option A is the correct one.
Let's see instead the names of the other options:
B. The farthest point in the Moon's orbit to Earth --> this point is called apogee
C. The closest point in Earth's orbit of the Sun --> this point is called perihelion
D. The Sun's orbit that is closest to the Moon --> this point has no specific name
Let the key is free falling, therefore from equation of motion
.
Take initial velocity, u=0, so
.

As velocity moves with constant velocity of 3.5 m/s, therefore we can use formula

From above substituting t,
.
Now substituting all the given values and g = 9.8 m/s^2, we get
.
Thus, the distance the boat was from the point of impact when the key was released is 10.60 m.
Answer:
a) T=1.35s
b) amplitude = 0.0923m
Explanation:
m=300 gr
k=6.5 N/m
first we need to get the angular frequency of the motion
so we have that
ω = √(k/m)
in this case motion is a simple harmonic so the period is defined by:
T= 2π / ω
T= 2π / √(k/m)
replacing the variables...
T= 2π / √(6.5/0.3)
T=1.35s (period of the block's motion)
and...
α max = | ω²r max |
2 = (2π/1.35)² * r max
r max= 0.0923m