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tatiyna
2 years ago
12

A 205 kg log is pulled up a ramp by means of a rope that

Physics
1 answer:
Volgvan2 years ago
7 0

Answer:2.737 kN

Explanation:

Given

mass of log(m)=205 kg

ramp inclination=30^{\circ}

coefficient of kinetic friction between log and ramp is (\mu _k)=0.9

log has an acceleration of 0.8 m/s^2

Let T be the tension in the rope

T-mgsin\theta -f_r=ma

Where mgsin\theta=Sin component of weight

f_r=friction\ Force=\mu _KN(Where N is Normal reaction)

T-mgsin\theta -\mu _k\left ( mgcos\theta \right )=ma

T=m\left ( gsin\theta +\mu _kcos\theta +a\right )

sin30=0.5

cos30=0.866

T=205\times \left ( 9.81\times 0.5+0.9\times 9.81\times 0.866+0.8\right )

T=205\times 13.35=2.737 kN

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A mass of 2000 kg. is raised 5.0 m in 10 seconds. What is the potential energy of the mass at this height?
kolbaska11 [484]

Answer:

98,000J

Explanation:

Given parameters :

Mass = 2000kg

Height = 5m

Time = 10s

P. E = mgh

P. E = 2000x 5x 9.8

P.E = 98,000J

5 0
2 years ago
A 1.50 cm high diamond ring is placed 20.0 cm from a concave mirror with radius of curvature 30.00 cm. The magnification is ____
Rama09 [41]

Answer:

Magnification, m = -0.42

Explanation:

It is given that,

Height of diamond ring, h = 1.5 cm

Object distance, u = -20 cm

Radius of curvature of concave mirror, R = 30 cm

Focal length of mirror, f = R/2 = -15 cm (focal length is negative for concave mirror)

Using mirror's formula :

\dfrac{1}{f}=\dfrac{1}{u}+\dfrac{1}{v}, f = focal length of the mirror

\dfrac{1}{v}=\dfrac{1}{f}+\dfrac{1}{u}

\dfrac{1}{v}=\dfrac{1}{-15}+\dfrac{1}{-20}

v = -8.57 cm

The magnification of a mirror is given by,

m=\dfrac{-v}{u}

m=\dfrac{-(-8.57)}{-20}

m = -0.42

So, the magnification of the concave mirror is 0.42. Thew negative sign shows that the image is inverted.

5 0
3 years ago
Convection is a process of heat transfer. In the earth, convection occurs because of heat and pressure from the core.
Aliun [14]

Answer:

I BELIEVE THE ANSWER A I REMEMBER THAT QUESTION WHEN I DID IT SO THATS THE BEST ONE OUT OF THE 3  

Explanation:

7 0
3 years ago
Read 2 more answers
At a department store, you adjust the mirrors in the dressing room so that they are parallel and 6.2 ft apart. You stand 1.8 ft
barxatty [35]

Answer:

<em>a) 3.6 ft</em>

<em>b) 12.4 ft</em>

Explanation:

Distance between mirrors = 6.2 ft

difference from from the mirror you face = 1.8 ft

a) you stand 1.8 ft in front of the mirror you face.

According to plane mirror rules, the image formed is the same distance inside the mirror surface as the distance of the object (you) from the mirror surface. From this,

your distance from your first "front" image = 1.8 ft + 1.8 ft = <em>3.6 ft</em>

b) The mirror behind you is 6.2 - 1.8 = 4.4 ft behind you.

the back mirror will be reflected 3.6 + 4.4 = 8 ft into the front mirror,

the first image of your back will be 4.4 ft into the back mirror,

therefore your distance from your first "back" image = 8 + 4.4 = <em>12.4 ft</em>

8 0
3 years ago
A radioactive material has a count rate of 400 per minute. It has a half life of 40 years. How long will it take to decay to a r
cestrela7 [59]

Answer:

160 years.

Explanation:

From the question given above, the following data were obtained:

Initial count rate (Cᵢ) = 400 count/min

Half-life (t½) = 40 years

Final count rate (Cբ) = 25 count/min

Time (t) =?

Next, we shall determine the number of half-lives that has elapse. This can be obtained as follow:

Initial count rate (Cᵢ) = 400 count/min

Final count rate (Cբ) = 25 count/min

Number of half-lives (n) =?

Cբ = 1/2ⁿ × Cᵢ

25 = 1/2ⁿ × 400

Cross multiply

25 × 2ⁿ = 400

Divide both side by 25

2ⁿ = 400/25

2ⁿ = 16

Express 16 in index form with 2 as the base

2ⁿ = 2⁴

n = 4

Thus, 4 half-lives has elapsed.

Finally, we shall determine the time taken for the radioactive material to decay to the rate of 25 counts per minute. This can be obtained as follow:

Half-life (t½) = 40 years

Number of half-lives (n) = 4

Time (t) =?

n = t / t½

4 = t / 40

Cross multiply

t = 4 × 40

t = 160 years.

Thus, it will take 160 years for the radioactive material to decay to the rate of 25 counts per minute.

7 0
2 years ago
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