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34kurt
3 years ago
13

A worker pushed a 25.0 kg block 6.50 m along a level floor at constant speed with a force directed 30.0° below the horizontal. I

f the coefficient of kinetic friction between block and floor was 0.410, what were (a) the work done by the worker's force and (b) the increase in thermal energy of the block-floor system?
Physics
1 answer:
Kipish [7]3 years ago
8 0

Answer:

a) 855.41J

b) 855.41J

Explanation:

The force equation is

N - mg - F sinθ = 0

N = mg + F sinθ

The frictonal  force is =

F_x = F cos \theta

U_xN = Fcos\theta

substitute the value of the normal force in the above equation

U_x (mg + Fsin\theta ) = F cos\theta

F = \frac{U_x mg}{cos\theta - U_x sin\theta } \\\\= \frac{0.41 \times 25 \times 9.8 }{cos 30^\circ- 0.41 \times sin30 ^\circ}

= 151.96N

a) work done = F × d

= (151.96) × (6.5) cos30°

= 855.41 J

b) The increase in thermal energy of the block floor system will be equal to the work done by the worker

work done = F × d

= (151.96) × (6.5) cos30°

= 855.41 J

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kaheart [24]

Answer:

B) t = 1.83 [s]

A) y = 16.51 [m]

Explanation:

To solve this problem we must use the following equation of kinematics.

v_{f} =v_{o} -g*t

where:

Vf = final velocity = 0

Vo = initial velocity = 18 [m/s]

g = gravity acceleration = 9.81 [m/s²]

t = time [s]

Note: the negative sign in the above equation means that the acceleration of gravity is acting in the opposite direction to the motion.

A) The maximum height is reached when the final velocity of the ball is zero.

0 = 18 - (9.81*t)

9.81*t = 18

t = 18/9.81

t = 1.83 [s], we found the answer for B.

Now using the following equation.

y = y_{o} + v_{o}*t - 0.5*g*t^{2}\\

where:

y = elevation [m]

Yo = initial elevation = 0

y = 18*(1.83) - 0.5*9.81*(1.83)²

y = 16.51 [m]

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3 years ago
How would you explain conduction?
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A research vessel is mapping the bottom of the ocean using sonar. It emits a short sound pulse called "ping" downward. The frequ
Svetradugi [14.3K]

Answer:

d = 4180.3m

wavelengt of sound is 0.251m

Explanation:

Given that

frequency of the sound is 5920 Hz

v=1485m/s

t=5.63s

let d represent distance from the vessel to the ocean bottom.

an echo travels a distance equivalent to 2d, that is to and fro after it reflects from the obstacle.

velocity=\frac{distance}{time}\\\\ v=\frac{2d}{t} \\\\vt=2d\\\\d=\frac{vt}{2}

d=\frac{1485*5.63}{2}\\d= 4180.3m

wavelengt of sound is \lambda = v/f

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natta225 [31]

Explanation:

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7 0
3 years ago
Sally and Sam are in a spaceship that comes to within 14,000 km of the asteroid Ceres. Determine the force Sally experiences, in
tatiyna

Sam and Sally are traveling aboard a spacecraft that approaches the asteroid Ceres within 14,000 kilometers. Sally will experience 1.989 × 10⁻¹¹  N of force.

<h3>What is the gravitational force?</h3>

Newton's law of gravity states that each particle having mass in the universe attracts each other particle with a force known as the gravitational force.

The gravitational force is proportional to the product of the masses of the two bodies and inversely proportional to the square of their distance.

Given data

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Mass of sally,m₂ = 67 kg

Gravitational constant,G = 6.6 × 10⁻¹¹ kg⁻² m²

Distance of seperation,R =  14,000 km

\rm F = G\frac{m_1m_2}{R^ 2} \\\\ F = 6.6 \times 10^{-11 }\times \frac{8.71020  \times 67 }{(14,000)^2}  \\\\F =  1.989 \times 10^{-11 } \ N

Hence, the force Sally experiences will be 1.989 × 10⁻¹¹  N.

To learn more about the gravitational force, refer to the link;

brainly.com/question/24783651

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