Let's choose east as positive x-direction and south as positive y-direction. We can resolve the two displacement along these two axes:
- Displacement 1 (3.5 km, south of west
- Displacement 2 (2.7 km, east of south
So, the total components on the two directions are
And the magnitude of the hiker's resultant displacement is
The first part of the text is missing, you can find on google:
"A ball is thrown horizontally from the roof of a building 45 m. If it strikes the ground 56 m away, find the following values."
Let's now solve the different parts.
(a) 3.03 s
The time of flight can be found by analyzing the vertical motion only. The vertical displacement at time t is given by
where
h = 45 m is the initial height
g = 9.8 m/s^2 is the acceleration of gravity
When y=0, the ball reaches the ground, so the time taken for this to happen can be found by substituting y=0 and solving for the time:
(b) 18.5 m/s
For this part, we need to analyze the horizontal motion only, which is a uniform motion at constant speed.
The horizontal position is given by
where
is the horizontal speed, which is constant
t is the time
At t = 3.03 s (time of flight), we know that the horizontal position is x = 56 m. By substituting these numbers and solving for vx, we find the horizontal speed:
The ball was thrown horizontally: this means that its initial vertical speed was zero, so 18.5 m/s was also its initial overall speed.
(c) 35.0 m/s at 58.1 degrees below the horizontal
At the impact, we know that the horizontal speed is still the same:
we need to find the vertical velocity. This can be done by using the equation
where
is the initial vertical velocity
g is the acceleration of gravity
t is the time
Substituting t = 3.03 s, we find the vertical velocity at the time of impact:
So the magnitude of the velocity at the impact (so, the speed at the impact) is
The angle instead can be found as:
so, 58.1 degrees below the horizontal.