Speed versus Time

If a rigid body rotates about a fixed axis passing through its center of mass, the body's linear momentum is

dexar [7]

Answer:

The linear momentum is zero

Explanation:

Because

When a rigid body is rotating about a fixed axis passing through point O, the body’s linear momentum given as L = mvG

But VG= 0 so

Linear momentum is zero

6 0

3 years ago

A wildlife researcher is tracking a flock of geese. The geese fly 4.0 km due west, then turn toward the north by 40º and fly ano

Kobotan [32]

Wildlife researcher starts from a and then reaches b, he turns towards north 40 degree to move towards c.

Total displacement is ac

Total horizontal displacement = 4+4 cos40 =7.06 km

Total vertical displacement = 4 sin40 =2.57 km

Total displacement $= \sqrt{7.06^2+2.57^2}$ = 7.51 km

7 0

3 years ago

Humans are a part of the Earth system. List at least three examples of how you, in particular, influence one or more of Earth’s

Naily [24]

Answer:

True, The humans have modified their environment the ecological system

Explanation:

Human is a part of the earth system and they are included in the ecological system that in particular is concerned with the provision of the feedback mechanism and cyclic flow of the system of energy such as the atmosphere, cryosphere, and the biosphere and the hydrosphere.

The human has already and influences the earth's physical system alike that of the atmospheric system in terms of the climate changes and the global warming that is taking place at a massive scale.

They are influencing the soil and land systems in terms of the depletion resources and the disturbing the hydrological cycles on earth that further influence the amounts of rainfall patterns.

The three examples given above are those of the use of the natural resources and thereby depletion of resources which are needed to sustain the functioning of the planet and various fields of the economics and the geology and that of the socio systems are also impacted and these forms the earth's major sphere of life.

8 0

3 years ago

2. A rocket blasts off vertically from rest on the launch pad with a constant upward acceleration of 2.5 . At 30.0 s after blast

harina [27]

Answer:

a)The highest point reached by the rocket is 1412 m

b)The rocket crashes after 54.7 s

Explanation:

Hi there!

The equations of height and velocity of the rocket are the following:

h = h0 + v0 · t + 1/2 · a · t² (while the engines work).

h = h0 + v0 · t + 1/2 · g · t² (when the rocket is in free fall).

v = v0 + a · t (while the engines work).

v = v0 + g · t (when the rocket is in free fall).

Where:

h = height of the rocket at a time t.

h0 = initial height of the rocket.

v0 = initial velocity.

t = time.

a = acceleration due to the engines.

g = acceleration due to gravity (-9.8 m/s² considering the upward direction as positive).

v = velocity of the rocket at a time t.

First, let's find the velocity and height reached by the rocket until the engines fail:

h = h0 + v0 · t + 1/2 · a · t²

Let's set the origin of the frame of reference at the launching point so that h0 = 0. Since the rocket starts from rest, v0 = 0. So after 30.0 s the height of the rocket will be:

h = 1/2 · a · t²

h = 1/2 · 2.5 m/s² · (30.0 s)²

h = 1125 m

Now let's find the velocity of the rocket at t = 30.0 s:

v = v0 + a · t (v0 = 0)

v = 2.5 m/s² · 30.0 s

v = 75 m/s

After 30.0s the rocket will continue to ascend with a velocity of 75 m/s. This velocity will be gradually reduced due to the acceleration of gravity. When the velocity is zero, the rocket will start to fall. At that time, the rocket is at its maximum height. So, let's find the time at which the velocity of the rocket is zero:

v = v0 + g · t

0 = 75 m/s - 9.8 m/s² · t (v0 = 75 m/s because the rocket begins its free-fall motion with that velocity).

-75 m/s / -9.8 m/s² = t

t = 7.7 s

Now, let's find the height of the rocket 7.7 s after the engines fail:

h = h0 + v0 · t + 1/2 · g · t²

The rocket begins its free fall at a height of 1125 m and with a velocity 75 m/s, then, h0 = 1125 m and v0 = 75 m/s:

h = 1125 m + 75 m/s · 7.7 s - 1/2 · 9.8 m/s² · (7.7 s)²

h = 1412 m

The highest point reached by the rocket is 1412 m

b) Now, let's calculate how much time it takes the rocket to reach a height of zero (i.e. to crash) from a height of 1412 m.

h = h0 + v0 · t + 1/2 · g · t² (v0 = 0 because at the maximum height the velocity is zero)

0 = 1412 m - 1/2 · 9.8 m/s² · t²

-1412 m / -4.9 m/s² = t²

t = 17 s

The rocket goes up for 30.0 s with an acceleration of 2.5 m/s².

Then, it goes up for 7.7 s with an acceleration of -9.8 m/s².

Finally, the rocket falls for 17 s with an acceleration of -9.8 m/s²

The rocket crashes after (30.0 s + 7.7 s + 17 s) 54.7 s

6 0

3 years ago

Two capacitors with capacitances of 3.25 and 5.00 μF, respectively, are connected in parallel. The system is connected to a 55-V

Nataliya [291]

The charge accumulated in 3.25 μF capacitor is 178.75 μC.

Answer:

Explanation:

In parallel connection, the voltage drop across any passive devices like capacitor or resistor will be constant. So the current flow will be varying in case of parallel connections of capacitors or resistors.

As the capacitance is the measure of amount of charge or current generated for a given amount of voltage, it is directly proportional to the charge or current and inversely proportional to voltage.

C = Q/V

Here the charge accumulated in a capacitor of capacitance 3.25 microfarad need to be determined which is in parallel connection with another capacitor. So the voltage through both the capacitor will be equal to the voltage of the battery which is stated as 55 V.

3.25× $10^{-6}$ = Q/55

Q = 3.25 * 55 = 178.75 μC

So the charge accumulated in 3.25 μF capacitor is 178.75 μC.

7 0

3 years ago