If a hockey player starts from rest and accelerates at a rate of 2.1 m/s², how long does it take him to skate 30 m?

You stand on a frictional platform that is rotating at 1.8 rev/s. Your arms are outstretched, and you hold a heavy weight in eac

dusya [7]

Answer:

20.62361 rad/s

489.81804 J

Explanation:

$I_i$ = Initial moment of inertia = 9.3 kgm²

$I_f$ = Final moment of inertia = 5.1 kgm²

$\omega_i$ = Initial angular speed = 1.8 rev/s

$\omega_f$ = Final angular speed

As the angular momentum of the system is conserved

$I_i\omega_i=I_f\omega_f\\\Rightarrow \omega_f=\dfrac{I_i\omega_i}{I_f}\\\Rightarrow \omega_f=\dfrac{9.3\times 1.8}{5.1}\\\Rightarrow \omega_f=3.28235\ rev/s=3.28235\times 2\pi=20.62361\ rad/s$

The resulting angular speed of the platform is 20.62361 rad/s

Change in kinetic energy is given by

$\Delta K=\dfrac{1}{2}(I_f\omega_f^2-I_i\omega_i^2)\\\Rightarrow \Delta K=\dfrac{1}{2}(5.1\times (20.62361)^2-9.3\times (1.8\times 2\pi)^2)\\\Rightarrow \Delta K=489.81804\ J$

The change in kinetic energy of the system is 489.81804 J

As the work was done to move the weight in there was an increase in kinetic energy

6 0

3 years ago

A rocket's mass decreases as it burns fuel. the equation of motion for a rocket in vertical flight can be obtained from newton's

Talja [164]

<span>The equation of motion for a rocket in vertical flight can be obtained from newton’s second law of motion and is constant-mass system. The equation of motion for a body mass varies with time and mass. When force acts on rocket, the rocket will accelerate in the direction of force. Therefore, force is equal to the change in momentum per change in time. For constant mass, force equals mass times acceleration.</span>

4 0

4 years ago

A spacecraft of mass 1500 kg orbits the earth at an altitude of approximately 450 km above the surface of the earth. Assuming a

PSYCHO15rus [73]

Answer:

1.28 x 10^4 N

Explanation:

m = 1500 kg, h = 450 km, radius of earth, R = 6400 km

Let the acceleration due to gravity at this height is g'

g' / g = {R / (R + h)}^2

g' / g = {6400 / (6850)}^2

g' = 8.55 m/s^2

The force between the spacecraft and teh earth is teh weight of teh spacecraft

W = m x g' = 1500 x 8.55 = 1.28 x 10^4 N

8 0

4 years ago

Which of the following forms of electromagnetic waves is LEAST dangerous to the human body?

makkiz [27]

<span>Which of the following forms of electromagnetic waves is LEAST dangerous to the human body? B
</span>

5 0

3 years ago

Read 2 more answers

Imagine you are charged to manage a project that aims to install wireless access points (aps) throughout the university campus.

Vitek1552 [10]

If you are charged to manage a project that aims to install wireless access points (aps) throughout the university campus, the steps to a foolproof plan for this project would be -

1. Recognize all of your network’s needs.

The most crucial step in any WiFi installation is probably knowing what your network needs are.

2. Select the appropriate hardware for your wireless network

Finding the ideal access point is much simpler if your needs are clear, but the wide range of options might be difficult.

3. Recognize your devices’ network restrictions.

It’s crucial to keep in mind that other factors besides your Internet connection and network hardware might affect how well your network performs.

4. Take into account the various cables you’ll need to use.

5. Consider how nearby interference may affect the installation of your wireless access point.

6. Decide where to put your wireless access point.

7. Analyze signal strength prior to making a decision.

To know more about access points (aps) visit:

brainly.com/question/14231305

#SPJ4

4 0

1 year ago