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3 years ago

Which of the following correctly compares a scientific investigation to a demonstration

2 answers:

8 0

Without options I can simply compare a scientific investigation to a demonstration:

<span>An investigation is a process when you are answering a question about the answer of which you do not know while a demonstration is a display or show of how something happens, when you already know the outcome.
</span>

Evgen [1.6K]3 years ago

5 0

An investigation is a process of answering a question; a demonstration shows the process of how something happens

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By means of a rope whose mass is negligible, two blocks are suspended over a pulley, as the drawing shows, with m1 = 12.1 kg and

puteri [66]

Answer:

14.8 kg

Explanation:

We are given that

$m_1=43.7 kg$

$m_2=12.1 kg$

$g=9.8 m/s^2$

$a=\frac{1}{2}(9.8)=4.9 m/s^2$

We have to find the mass of the pulley.

According to question

$T_2-m_2 g=m_2 a$

$T_2=m_2a+m_2g=m_2(a+g)=12.1(9.8+4.9)=177.87 N$

$T_1=m_1(g-a)=43.7(9.8-4.9)=214.13 N$

Moment of inertia of pulley= $I=\frac{1}{2}Mr^2$

$(T_2-T_1)r=I(-\alpha)=\frac{1}{2}Mr^2(\frac{-a}{r})=\frac{1}{2}Mr(-4.9)$

Where $\alpha=\frac{a}{r}$

$(177.87-214.13)=-\frac{1}{2}(4.9)M$

$-36.26=-\frac{1}{2}(4.9)M$

$M=\frac{36.26\times 2}{4.9}=14.8 kg$

Hence, the mass of the pulley=14.8 kg

6 0

3 years ago

An astronaut is traveling in a space vehicle moving at 0.490c relative to the Earth. The astronaut measures her pulse rate at 66

marta [7]

To solve the exercise it is necessary to use the reciprocal Lorenz factor of the special theory of relativity with the pulse rate.

$\Xi = Pulse_{astronaut} * \alpha$

Where,

$\Xi =$ Pulse rate measured by earth observed

$\alpha =$ Reciprocal Lorenz Factor

$\alpha = \sqrt{1-\frac{v^2}{c^2}}$

Here v is the velocity and c the light speed.

PART A) For the given values we can replace it at the previous equation,

$\Xi = Pulse_{astronaut} *\sqrt{1-\frac{v^2}{c^2}}$

$\Xi = 66beats/min * \sqrt{1-\frac{(0.49c)^2}{c^2}}$

$\Xi = 57.5beats/min$

PART B ) If the speed of vehicle is 0.94c:

$\Xi = Pulse_{astronaut} *\sqrt{1-\frac{v^2}{c^2}}$

$\Xi = 66beats/min * \sqrt{1-\frac{(0.94c)^2}{c^2}}$

$\Xi = 22.5beats/min$

8 0

3 years ago

A bullet can travel at a speed of over 1000 m/s. When a bullet is fired from a rifle, the actual firing makes a distinctive soun

slamgirl [31]

Explanation:

When a bullet is fired from a rifle, the actual firing makes a distinctive sound, but people at a distance may hear a second because the bullet creates a shock wave , a little sonic boom( speed of this sonic boom is greater than the speed of sound). It is this sound only that is heard by the people at a distance from the gun.

7 0

3 years ago

Calculate the work done by a 47N force pushing a pencil against a force of 23 N

stira [4]

I believe the answer would be 24N
Explanation: Because the forces are going against each other, in order to calculate the work done we need to subtract them. 47-23=24

8 0

2 years ago

Jack and Jill are on two different floors of their high rise office building and looking out of their respective windows. Jack s

Maru [420]

Answer:

a) speed when Jack sees the pot : 12.92 meters per second

b) height difference 163.115 meters

Explanation:

First to calculate te initial speed we use the acceleration formula:

a= v1-v0/t

Acceleration being gravity's acceleration (9.8 m/s^2)

v1 being the speed when Jill sees the pot

v0 when Jack sees it

and t the time between

Solving for v0 it would be

v1 - a*t = v0

replacing

$58 m/s - 9.8 m/s^2 *4.6 s = v0 = 12.92 m/s$

For the second question we use the position formula setting y0 and t0 as the position and time when jack sees the pot. (and setting the positive axis downward I.E. one meter below jack would be 1m not -1m)

The formula is

$y0 + v0*t + 1/2 g *t^2 = yt$

replacing

$0m + 12.92m/s* 4.6 s + 1/2 * 9.8 m/s^2 * (4.6 s)^2 = 163.115 m$

5 0

3 years ago