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ahrayia [7]
2 years ago
7

The block brake consists of a pin-connected lever and friction block at B. The coefficient of static friction between the wheel

and the lever is μs = 0.3, and a torque of 5 N⋅m is applied to the wheel. Determine if the brake can hold the wheel stationary when the force applied to the lever is (a) P = 30 N, (b) P = 70 N.
Physics
2 answers:
ANTONII [103]2 years ago
7 0

Answer:

B

Explanation:

Nina [5.8K]2 years ago
7 0

Answer:

a) Insufficient

b) Sufficient

Explanation:

To hold lever:

Sum of moments about point O center of wheel = 0

Fb * 0.15 - 5 =0

Fb = 33.33N

Contact force Nb:

Nb = (Fb/u) = (33.333 / 0.3) = 111.1 N

Sum of moments about point A lever pin joint = 0

Preq * 0.6 - 111.1*0.2 - 33.33*0.05 = 0

Preq = 39.8 N

part a

P = 30N < Preq = 39.8N

Hence, insufficient

part b

P = 70N > Preq = 39.8N

Hence, sufficient

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An experiment to measure the speed of light uses an apparatus similar to Fizeau's. The distance between the light source and the
Marina86 [1]

Answer:

2.88*10^{8} m/s

Explanation:

The speed of light is given by

c=\frac {2d}{t} and t=\frac {\theta}{\omega} hence

c=\omega\frac {2d}{\theta}

Speed of light is given by

c=900\times 2\pi(\frac {2\times 10}{\frac {2\pi}{2*800}}})=2.88*10^{8} m/s

4 0
2 years ago
The energy stored in a wooden log transforms when the log is burned. Which of the following explanations BEST describes how the
Makovka662 [10]

Answer:

D. the amount of chemical energy equals the amount of heat and light energy.

Explanation:

Given that the first law of thermodynamics affirmed that energy is neither created nor destroyed however, it can be transformed from one form to another. In other words, while, during the transformation of energy, no energy is lost, the input energy is also equal to output energy.

Hence, the chemical energy stored in the log is EQUAL to the heat and light energy produced by burning.

5 0
2 years ago
If you wished to warm 100 kg of water by 15 degrees celsius for your bath, how much heat would be required? (give your answer in
Anit [1.1K]
For the answer to the question above, 
<span>Q = amount of heat (kJ) </span>
<span>cp = specific heat capacity (kJ/kg.K) = 4.187 kJ/kgK </span>
<span>m = mass (kg) </span>
<span>dT = temperature difference between hot and cold side (K). Note: dt in °C = dt in Kelvin </span>

<span>Q = 100kg * (4.187 kJ/kgK) * 15 K </span>
<span>Q = 6,280.5 KJ = 6,280,500 J = 1,501,075.5 cal</span>
6 0
2 years ago
The force F required to compress a spring a distance x is given by F 2 F0 5 kx where k is the spring constant and F0 is the prel
IrinaVladis [17]

Answer:

a)W=8.333lbf.ft

b)W=0.0107 Btu.

Explanation:

<u>Complete question</u>

The force F required to compress a spring a distance x is given by F– F0 = kx where k is the spring constant and F0 is the preload. Determine the work required to compress a spring whose spring constant is k= 200 lbf/in a distance of one inch starting from its free length where F0 = 0 lbf. Express your answer in both lbf-ft and Btu.

Solution

Preload = F₀=0 lbf

Spring constant k= 200 lbf/in

Initial length of spring x₁=0

Final length of spring x₂= 1 in

At any point, the force during deflection of a spring is given by;

F= F₀× kx  where F₀ initial force, k is spring constant and x is the deflection from original point of the spring.

W=\int\limits^2_1 {} \, Fds \\\\\\W=\int\limits^2_1( {F_0+kx} \,) dx \\\\\\W=\int\limits^a_b {kx} \, dx ; F_0=0\\\\\\W=k\int\limits^2_1 {x} \, dx \\\\\\W=k*\frac{1}{2} (x_2^{2}-x_1^{2}  )\\\\\\W=200*\frac{1}{2} (1^2-0)\\\\\\W=100.lbf.in\\\\

Change to lbf.ft by dividing the value by 12 because 1ft=12 in

100/12 = 8.333 lbf.ft

work required to compress the spring, W=8.333lbf.ft

The work required to compress the spring in Btu will be;

1 Btu= 778 lbf.ft

?= 8.333 lbf.ft----------------cross multiply

(8.333*1)/ 778 =0.0107 Btu.

6 0
2 years ago
In Physics lab, Ellen has been given the task of constructing a simple motor. She must find common household items at home and b
Aleks [24]

Answer:

a) battery-->electrical current-->copper wire rotor -->magnet--> mechanical energy

Explanation:

6 0
2 years ago
Read 2 more answers
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