All categories

3 years ago

I'm new to brainy, but here is my question.

Physics

2 answers:

skad [1K]3 years ago

8 0

680 is the right answer

Fittoniya [83]3 years ago

7 0

Answer: 680 J

Explanation:

Andre's mechanical energy is given by:

$E=K+U$

where

K is the kinetic energy

U is the gravitational potential energy

The kinetic energy in this case is zero, because Andre is sitting, so its speed is zero: v=0, and the kinetic energy is

$K=\frac{1}{2}mv^2=\frac{1}{2}(77.1 kg)(0)^2=0$

The gravitational potential energy is instead

$U=mgh=(77.1 kg)(9.8 m/s^2)(0.90 m)=680.0 J$

So, the total mechanical energy is

$E=U=680.0 J$

You might be interested in

An object has a mass of 2,000kg. what is its weight on earth? show your work

artcher [175]

Answer:

F=m*g is the formula and the answer is 19,620 kg

Explanation:

Since the formula is F=m*g and Earth's gravity is 9.81 m/s^2 all you need to do is multiply 2,000 by 9.81

6 0

2 years ago

Read 2 more answers

When an astronomer sees certain stars and galaxies that look much redder than expected, what conclusion might the astronomer dra

Ratling [72]

It all comes to the doppler effect, the red shift means that the galaxy is moving away from us. The redshift is a result from the doppler effect, so as the galaxy moves away the wavelength expands, increasing the wavelength which responds to the red light.

8 0

3 years ago

Read 2 more answers

Help meh in this question plzzz <br>

iragen [17]

The Moment of Inertia of the Disc is represented by $I = \frac{15}{32}\cdot M\cdot R^{2}$ . (Correct answer: A)

Let suppose that the Disk is a Rigid Body whose mass is uniformly distributed. The Moment of Inertia of the element is equal to the Moment of Inertia of the entire Disk minus the Moment of Inertia of the Hole, that is to say:

$I = I_{D} - I_{H}$ (1)

Where:

$I_{D}$ - Moment of inertia of the Disk.

$I_{H}$ - Moment of inertia of the Hole.

Then, this formula is expanded as follows:

$I = \frac{1}{2}\cdot M\cdot R^{2} - \frac{1}{2}\cdot m\cdot \left(\frac{1}{2}\cdot R^{2} \right)$ (1b)

Dimensionally speaking, Mass is directly proportional to the square of the Radius, then we derive the following expression for the Mass removed by the Hole ( $m$ ):