Answer:
It took the projectile 120 s to reach the maximum height.
Explanation:
Given;
maximum height of the projectile, s = 180 km = 180,000 m
initial speed of the projectile, u = 3 km/s = 3000 m/s
final velocity at maximum height, v = 0
Apply the following kinematic equation for average velocity of the projectile;
Therefore, it took the projectile 120 s to reach the maximum height.
156.8 Joules of energy is in the box's gravitational potential energy store
<u>Explanation</u>:
<em>Given:</em>
Mass of the box Dane is holding = 8 Kilograms
Height at which Dane is holding the box above the ground= 2 metres
<em>To Find:</em>
Gravitational potential energy in the box=?
<em>Solution:</em>
gravitational potential energy is the work done per mass on a object to move that object from one fixed location to to another location against gravity.Its unit is joules or J
Thus Gravitational potential energy is represented as,
where
is the gravitational potential energy
m is the mass
h is the height
g is the gravitational force( 9.8 )
Now substituting the given values,
Answer:
v_wind = 101.46 km / h , θ = 61.8
Explanation:
This is a velocity composition exercise.
Let's do the problem in parts. Let's start by knowing the speed of the plane without air.
v = d / t
v = 750 / 3.14
v = 238.85 km / h
This is the speed of the plane relative to the Earth and it does not change.
In the second part, when there is wind, the travel time is greater than when there is no wind, therefore the wind delays the plane. To be more general, suppose that the wind has two components vₓ and
Let's use trigonometry to find the components of the plane's speed
cos θ = v_N / v
sin θ = v_W / v
v_N = v cos θ
v_W = v sin θ
let's calculate
V _N = 238.85 cos 22 = 221.46 km / h
v_W = -238.85 sin 22 = -89.47
the negative sign is because the plane is going west and the positive sign is the east direction.
As it indicates that the destination of the avine is towards the north, the x component of the wind must be
vₓ - v_W = 0
vₓ = v-w
vₓ = 89.47 km / h
in the direction to the East.
Now let's analyze the component of the wind in the Nort-South direction,
Indicate the travel time, let's calculate the speed that the component must have the speed of the plane
v_total = d / t
v_total = 750 / 4.32
v_total = 173.61 km / h
This is the final speed of the plane, which can be written
v_total = v_n - vy
vy = v_n - v_total
vy = 221.46 - 173.61
vy = 47.85 km
this component is directed towards the south
Let's use the Pythagorean Theorem, to find the magnitude
v_wind² = vₓ² + vy²
v_wind = √ (89.47² + 47.85²)
v_wind = 101.46 km / h
the address will then be found using trigonometry
θ = Vy / vx
θ = tan⁻¹ (vy / vx)
θ = tan⁻¹1 (47.85 / 89.47)
θ = 28.14
Therefore, the magnitude of the wind speed is 101.5 km / h and its direction is 28º south of the East, to give this value
90- θtea = 90- 28.2
θ = 61.8
East of South