All categories

2 years ago

Police officer at rest at the side of the highway

1 answer:

4 0

Let's take the police officers starting position as our origin, that is Sp(t0) = Ss(t0) = 0, and, since we know the police officers starts from a standstill, Vp(t0) = 0 and Vs(t0) = 62km/h

For the first part of the pursuit, during the officers acceleration:

Sp(t) = Sp(t0) + Vp(t0)*t + (3/2)*t^2

Sp(t) = 1.5*t^2

Vp(t) = 3*t

We need to know how much time transpires during this first bit, that is until the officers speed is 72 km/h or 20m/s, and we can find that out by using Vp(t):

Vp(t1) = 20 = 3*t1

t1 = 3.33... s

We now look at how much space each of them covers during this time:

Sp(t1) = 1.5*(t1)^2 = 16.66... m

Ss(t1) = Vs*t1 = (62/3.6)*(3.33...) = 57.41 m

For the second part of the pursuit we will take the officers position as our origin:

Sp(t) = 20*t

Ss(t) = (57.41 - 16.66) + (17.22...)*t

Now we just need to equate Sp(t) to Ss(t):

20*t = (40.75) + (17.22...)*t

t = 40.75/(2.77...) = 14.67 s

But we need to add the time in the first part of the pursuit to the time we just found:

14.67 + 3.33 = 18s

The pursuit lasts 18 seconds.

You might be interested in

A cubical shell with edges of length a is positioned so that two adjacent sides of one face are coincident with the +x and +y ax

Bingel [31]

Answer:

Q = ba⁴ * ε₀

Explanation:

From Gauss's Law, we know that

flux Φ = Q / ε₀

where ε₀ = 8.85e-12 C²/N·m²

and also,

Φ = EAcosθ

The field is directed along the x-axis, so that all of the flux passes through the side of the cube at x = a. This means that θ = 0º, and thus

Φ = EAcos0

Φ = EA

E = bx² meanwhile, we are interested in the point where x = a, so we substitute and then

E = ba²

Since A = a² for the cube face, we have

Q / ε₀ = E * A

Q / ε₀ = ba² * a²

so that

Q = ba⁴ * ε₀

5 0

2 years ago

The absolute pressure, in kilopascals, a depth 10m below sea level is most nearly?

saul85 [17]

Answer:

option A

Explanation:

given,

depth of the sea level = 10 m

g = 10 m/s²

Pressure underwater = ?

we know,

P = ρ g h

where ρ is the density of water which is equal to 1000 kg/m³

h is the depth of sea level

P = ρ g h

P = 1000 x 10 x 10

P = 100000 Pa

P = 100 kPa

Hence, the correct answer is option A

8 0

2 years ago

A cylinder is sliced in half along its diagonal. Determine the location of the center of mass and the inertia properties relativ

Black_prince [1.1K]

Answer:

See the explanation below

Explanation:

To better understand this problem, a cylinder sketch is attached before and after the cut, we see that after the cut, the shape of this resembles that of a right triangle.

We can find, the centroid in the xy plane, knowing that the centroid for a triangle is located a third of its base.

In the z axis there is no displacement of the centroid.