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Setler [38]
3 years ago
5

Help me out guysI'm stuck in this ​

Physics
1 answer:
Juli2301 [7.4K]3 years ago
6 0

Answer: The answer will be R1 = B

Explanation:

Cause Here x component of A = A

X component of 2B       = 2BcosФ

X component of Resultant = 0

I.e. A + 2BcosФ = 0

cosФ = -A/2B

also R1 = √(A² + B² + 2ABcosФ)

            =√ [A² + B² + 2AB(-A/2B)]

            =√A² + B² -A²

R1 = √B²

R1 = B so R1 = B is correct.

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1.An elevator is ascending with constant speed of 10 m/s. A boy in the elevator throws a ball upward at 20 m/ a from a height of
laiz [17]

(a) The maximum height reached by the ball from the ground level is 75.87m

(b) The time taken for the ball to return to the elevator floor is 2.21 s

<u>The given parameters include:</u>

  • constant velocity of the elevator, u₁ = 10 m/s
  • initial velocity of the ball, u₂ = 20 m/s
  • height of the boy above the elevator floor, h₁ = 2 m
  • height of the elevator above the ground, h₂ = 28 m

To calculate:

(a) the maximum height of the projectile

total initial velocity of the projectile = 10 m/s + 20 m/s  = 30 m/s (since the elevator is ascending at a constant speed)

at maximum height the final velocity of the projectile (ball), v = 0

Apply the following kinematic equation to determine the maximum height of the projectile.

v^2 = u^2 + 2(-g)h_3\\\\where;\\\\g \ is \ the \ acceleration \ due \ to\  gravity = 9.81 \ m/s^2\\\\h_3 \ is \ maximum \ height \ reached \ by \ the \ ball \ from \ the \ point \ of \ projection\\\\0 = u^2 -2gh_3\\\\2gh_3 = u^2 \\\\h_3 = \frac{u^2}{2g} \\\\h_3 = \frac{(30)^2}{2\times 9.81} \\\\h_3 = 45.87 \ m

The maximum height reached by the ball from the ground level (h) = height of the elevator from the ground level + height of he boy above the elevator + maximum height reached by elevator from the point of projection

h = h₁ + h₂ + h₃

h = 28 m + 2 m  +  45.87 m

h = 75.87 m

(b) The time taken for the ball to return to the elevator floor

Final height of the ball above the elevator floor = 2 m + 45.87 m = 47.87 m

Apply the following kinematic equation to determine the time to return to the elevator floor.

h = vt + \frac{1}{2} gt^2\\\\where;\\\\v \ is \ the \ initial \ velocity \ of \ the \ ball \ at \ the \ maximum \ height = 0\\\\h = \frac{1}{2} gt^2\\\\gt^2 = 2h\\\\t^2 = \frac{2h}{g} \\\\t = \sqrt{\frac{2h}{g}} \\\\t = \sqrt{\frac{2\times 47.87}{9.81}} \\\\t = 2.21 \ s

To learn more about projectile calculations please visit: brainly.com/question/14083704

6 0
3 years ago
If a diffraction grating has 3700 lines per cm, what is the spacing d between lines
Sonja [21]
So first we find the gap between the slits by the formula d=1/N 

<span>N is number of lines per metre so 3700 line/cm = 370000 lines/m </span>
<span>So d=2.7*10^-6 </span>

<span>Now we use the formula dsin(angle)=n(wavelength) </span>

<span>d is the same </span>
<span>n is the order of the diffraction pattern </span>

<span>so wavelenth=dsin(angle)/n </span>
<span>=[(2.7*10^-6)*sin30]/3 </span>
<span>=4.5*10^-7 m</span>
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An input for of 80 N is used to lift an object weighing 240 N with a system of pulleys. How far must the rope around the pulleys
sammy [17]

Answer:

4.2 m

Explanation:

Note: If energy is conserved, i.e no work is done against friction

Work input = work output.

Work output = Force output × distance,

Work input = force input × distance moved moved.

Therefore,

input force×distance moved = output force × distance moved........................Equation 1

Given: input force = 80 N, output force = 240 N, output distance = 1.4 m

Let input distance = d

Substitute into equation 1

80×d = 240×1.4

80d = 336

d = 336/80

d = 4.2 m.

Thus the rope around the pulley must be pulled 4.2 m

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The correct answer is The storage and management of radioactive wastes

Explanation:

In general, nuclear reactions (changes in the nucleus of an atom such as fission) release a lot of energy including a lot of heat. Moreover, this heat is used by humans to obtain electricity and other types of energy, which is known as a nuclear power. This type of power is considered positive because it does not emit carbon and it is quite efficient.

However, in most cases, it is a threat to the environment and living beings because storing and managing the wastes of this type of power is difficult and expensive. Indeed, dealing with the wastes of nuclear power requires complex infrastructure, and any accident or leaking leads to serious consequences from the death of those exposed to the wastes to permanent loss of diversity or changes in nearby areas.

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Explanation:

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