A pelican flying along a horizontal path drops
a fish from a height of 5.0 m. The fish travels
8.5 m horizontally before it hits the water
below.
The acceleration of gravity is 9.81 m/s2 .
a) What was the pelican’s initial speed?
Answer in units of m/s
Divide 8.5 m by the time it takes the fish to fall 5.0 m
7.6/3.3
To find the pelican's initial speed, we can use the kinematic equations of motion. Let's break down the problem:
1. We have the vertical height, which is 5.0 m.
2. The fish travels horizontally for a distance of 8.5 m before hitting the water.
3. The acceleration due to gravity is 9.81 m/s².
First, let's find the time it takes for the fish to hit the water using the equation for vertical motion:
h = (1/2)gt²
Where:
h is the height (5.0 m)
g is the acceleration due to gravity (9.81 m/s²)
t is the time
Rearranging the equation and substituting the known values:
t = sqrt(2h/g)
t = sqrt(2 * 5.0 m / 9.81 m/s²)
t ≈ 1.02 s (rounded to two decimal places)
Now that we have the time, let's find the initial horizontal velocity (speed) of the pelican using the equation:
v = d/t
Where:
v is the initial velocity
d is the horizontal distance (8.5 m)
t is the time (1.02 s)
v = 8.5 m / 1.02 s
v ≈ 8.33 m/s (rounded to two decimal places)
Therefore, the pelican's initial speed was approximately 8.33 m/s.