The answer is a because it has a high melting tolerance
Answer:
a) 0.32 m b) -2.4 m c) 1.08 m/s d) -4 m/s
Explanation:
a)
- As the x and y axes (as chosen) are perpendicular each other, the movements along these axes are independent each other.
- This means that we can use the kinematic equations for displacements along both axes.
- In the x direction, as the only initial velocity is in the south direction (-y axis), the skateboarder is at rest, so we can write:

- In the y-direction, as no acceleration is acting on the skateboarder, we can write the following displacement equation:

- For t = 0.6s, replacing by the givens, we get the position (displacement from the origin) on the x-axis, as follows:

b)
- From (2) we can get the position on the y-axis (displacement from the origin) as follows:

c)
- In the x- direction, we can find the component of the velocity along this direction, as follows:

- Replacing by the values, we have:

d)
- As the skateboarder moves along the y-axis at a constant speed equal to her initial velocity, we have:
vfy = voy = -4 m/s
There are several information's already given in the question. Based on those information's the answer can be easily deduced.
Speed of the truck = 70 kph
= 19.44 m/s
Speed of sound = 343 m/s
Then
Observed frequency = 400 Hz ∗ 343 m/s/<span>19.44m/s + 343 m/<span>s
= 378.54
= 379 Hz</span></span>