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3 years ago

We cannot consider something to be work unless

Physics

2 answers:

iren [92.7K]3 years ago

5 0

<span>force applied causes movement of an object in the same direction as the applied force.</span>

kari74 [83]3 years ago

5 0

Explanation:

The product of applied force and the displacement is called the amount of work done by an object. For the work to be done the force and the displacement are two important factors. The mathematical expression for the work done is given by :

$W=Fd\ cos\theta$

Where

$\theta$ is the angle between applied force and the displacement

When $\theta=90$ , W = 0

$\theta=0$ , W = F d

$\theta=180$ , W = -F d

So, we cannot consider something to be work unless force applied causes movement of an object in the same direction as the applied force. Hence, this is the required solution.

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the earth has more rotational kinetic energy now than did the cloud of gas and dust from which it formed. where did this energy

goldfiish [28.3K]

Explanation:

Earth or any planet are actually born from huge clouds of gas and dust. Their stellar mass are fairly distributed at a radius from the axis of rotation. Gravitational force cause the cloud to come together. Now the whole gathered in smaller area. Now, individual particles come close to the roational axis. Thus, decreasing the moment of inertia of the planet.

I=mr^2

reducing r reduces I. However, the angular moment of the system remains always conserved. So, to conserve the angular momentum the angular velocity of the planet increases and so did the otational kinetic energy

3 0

2 years ago

4. A group of students made a rocket and launched it vertically upwards with velocity

Aleks04 [339]

Answer:

Approximately $72.9\; \rm m$ , assuming that the rocket had no propulsion onboard, and that air resistance on the rocket is negligible.

Explanation:

Initial velocity of this rocket: $u = 27\; \rm m\cdot s^{-1}$ .

When the rocket is at its maximum height, the velocity of the rocket would be equal to $0$ . That is: $v = 0\; \rm m \cdot s^{-1}$ .

The acceleration of the rocket (because of gravity) is constantly downwards, with a value of $a = -g = -10\; \rm m \cdot s^{-2}$ .

Let $x$ denote the distance that the rocket travelled from the launch site to the place where it attained maximum height. The following equation would relate $x \!$ to $u$ , $v$ , and $a$ :

$\displaystyle x = \frac{v^2 - u^2}{2\, a}$ .

Apply this equation to find the value of $x$ :

$\begin{aligned} x &= \frac{v^2 - u^2}{2\, a} \\ &= \frac{\left(0\; \rm m\cdot s^{-1}\right)^{2} - \left(27\; \rm m \cdot s^{-1}\right)^{2}}{2 \times 10\; \rm m \cdot s^{-2}} = 36.45\; \rm m\end{aligned}$ .

In other words, the maximum height that this rocket attained would be $36.45\; \rm m$ .

Again, assume that the air resistance on this rocket is negligible. The rocket would return to the ground along the same path, and would cover a total distance of $2\times 36.45\; \rm m = 72.9\; \rm m$ .

7 0

3 years ago

If you enjoyed teaching small or large classes and being active every day which career would be a good fit for you

Vlad [161]

You will probably be fit to be a elementary school teacher

4 0

2 years ago

Who invented the first telescope

mylen [45]

Answer:

Hans Lipperhey

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5 0

2 years ago

Read 2 more answers

At a particular instant, a moving body has a kinetic energy of 295 J and a momentum of magnitude 25.1 kg · m/s.(a)What is the sp

motikmotik

Answer:

a) 23.51 m/s

b) 1.07 kg

Explanation:

Parameters given:

Kinetic energy, K = 295 J

Momentum, p = 25.1 kgm/s

a) The kinetic energy of a body is given as:

$K = \frac{1}{2} mv^2$

where m = mass of the body and v = speed of the body

We know that momentum is given as:

p = mv

Therefore:

K = 1/2 * pv

=> v = 2K / p

v = (2 * 295) / 25.1 = 23.51 m/s

The velocity of the body at that instant is 23.51 m/s.

b) Momentum is given as:

p = mv

=> m = p / v

m = 25.1 / 23.51 = 1.07 kg

The mass of the body at that instant is 1.07 kg

5 0

2 years ago