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VARVARA [1.3K]
4 years ago
13

WILL GIVE BRAINLIEST AND 60 POINTS!

Physics
1 answer:
Arte-miy333 [17]4 years ago
8 0

Answer:

The answer is d y:radio z:gamma rays

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If gravity on mars is less that that of earth so you weigh more or less on mars
Leokris [45]

Answer:

Less

Explanation:

4 0
3 years ago
Read 2 more answers
A horizontal spring is lying on a frictionless surface. One end of the spring is attaches to a wall while the other end is conne
JulsSmile [24]

Answer:

v_f = 1.05 m/s

Explanation:

From conservation of energy;

E_f = E_i

Thus,

(1/2)m(v_f)² + (1/2)I(ω_f)² + m•g•h_f + (1/2)k•(x_f)² = (1/2)m(v_i)² + (1/2)I(ω_i)² + m•g•h_i + (1/2)k•(x_i)²

This reduces to;

(1/2)m(v_f)² + (1/2)Ik(x_f)² = (1/2)k•(x_i)²

Making v_f the subject, we have;

v_f = [√(k/m)] * [√((x_i)² - (x_f)²)]

We know that ω = √(k/m)

Thus,

v_f = ω[√((x_i)² - (x_f)²)]

Plugging in the relevant values to obtain;

v_f = 17.8[√((0.068)² - (0.034)²)]

v_f = 17.8[0.059] = 1.05 m/s

3 0
3 years ago
Find the resistance at 50°c of copper wire 2mm in diameter and 3m long
mr Goodwill [35]
0.0179 ohms for copper.

0.0184 ohms for annealed copper



Ď = R (A/l) where

Ď = electrical resistivity

R = electrical resistance of a uniform specimen

A = cross sectional area

l = length



Solve for R by multiplying both sides by l/A

R = Ď(l/A)



The cross section of the wire is pi * 1^2 mm = 3.14159 square mm = 3.14159e-6 square meters.

The length is 3 meters. So l/A = 3/3.14159e-6 = 9.5493e5



Ď for copper is 1.68e-8 so 1.68e-8 * 9.5493e5 = 1.60e-2 ohms at 20 C

But copper has a temperature coefficient (α) of 0.00386 per degree C.

So the resistance value needs to be adjusted based upon how far from 20 C the temperature is.

50 - 20 = 30 C

So 0.00386 * 30 = 0.1158 meaning that the actual resistance at 50 C will be 11.58% higher.

So 1.1158 * 0.016 = 0.0179 ohms.



If you're using annealed copper, the values for Ď and the temperature coefficient change.

Ď = 1.72e-8

α = 0.00393



Doing the math, you get

1.72e-8 * 9.5493e5 * (1 + 30 * 0.00393) = 0.0184 ohms
8 0
3 years ago
1) [25 pts] A 90-kg merry-go-round of radius 2.0 m is spinning at a constant speed of 20 revolutions per minute. A kid standing
Ray Of Light [21]

Answer:

(A) 180 kg·m²

(B) 0.111 rad/s²

(C) The number of revolutions the merry-go-round will complete until it finally stops is 3.142 or π rev

Explanation:

The equation of the moment of inertia of a solid cylinder is presented as follows;

I = \frac{1}{2}MR^2

Where:

I = Moment of inertia of the merry-go-round

M = Mass of the merry-go-round

R = Radius of the merry-go-round

Therefore, I = 1/2×90×2² = 180 kg·m²

(B) For the angular acceleration we have;

Therefore, since the force × radius = The torque, we have, angular acceleration is found as follows

F × R = τ

10.0 × 2.0 = 20 = I×α = 180×α

α = 20/180 = 0.111 rad/s².

angular acceleration = 0.111 rad/s².

(C) Here we have ω₀ = 20 rev/ min = 20×2×π rad/min = π·40/60 rad/s

2/3·π rad/s

ω = ω₀ - α×t

∴ t = ω₀/α = (2/3·π rad/s)/(0.111 rad/s²) = 18.85 s

Hence we have

θ = ω₀·t + 1/2·α·t², plugging in the values, we have;

θ = 2/3·π×18.85 - 1/2·0.111·18.85²

θ = 19.74 rad

Therefore, since 2·π radian = 1 revolution

The number of revolutions the merry-go-round will complete until it stops is 19.74/(2·π) = 3.142 or π revolutions.

5 0
4 years ago
Which of the following safety devices provides a weak link in a circuit that will melt if it received too much current, thus bre
SVETLANKA909090 [29]
The correct answer is B. Fuse.

Fuses were commonly used in houses up to recent ages, when circuit breakers became the more popular options, as they don't have to be changed every time they melt, since they don't melt.
4 0
3 years ago
Read 2 more answers
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