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2 years ago

5

Two flywheels of negligible mass and different radii are bonded together and rotate about a common axis (see below). The smaller

flywheel of radius 30 cm has a cord that has a pulling force of 50 N on it. What pulling force needs to be applied to the cord connecting the larger flywheel of radius 50 cm such that the combination does not rotate?

1 answer:

jeka942 years ago

8 0

Answer:

Explanation:

Torque on smaller wheel

= F x r

50 x .30

= 15 Nm

Torque on larger wheel

= F x .5

For equilibrium

F x .5 = 15

F = 15 / .5

= 30 N

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Evaporation of sweat requires energy and thus take excess heat away from the body. Some of the water that you drink may eventual

kotegsom [21]

Answer:

The amount of heat required is $H_t = 1.37 *10^{6} \ J$

Explanation:

From the question we are told that

The mass of water is $m_w = 20 \ ounce = 20 * 28.3495 = 5.7 *10^2 g$

The temperature of the water before drinking is $T_w = 3.8 ^oC$

The temperature of the body is $T_b = 36.6^oC$

Generally the amount of heat required to move the water from its former temperature to the body temperature is

$H= m_w * c_w * \Delta T$

Here $c_w$ is the specific heat of water with value $c_w = 4.18 J/g^oC$

So

$H= 5.7 *10^2 * 4.18 * (36.6 - 3.8)$

=> $H= 7.8 *10^{4} \ J$

Generally the no of mole of sweat present mass of water is

$n = \frac{m_w}{Z_s}$

Here $Z_w$ is the molar mass of sweat with value

$Z_w = 18.015 g/mol$

=> $n = \frac{5.7 *10^2}{18.015}$

=> $n = 31.6 \ moles$

Generally the heat required to vaporize the number of moles of the sweat is mathematically represented as

$H_v = n * L_v$

Here $L_v$ is the latent heat of vaporization with value $L_v = 7 *10^{3} J/mol$

=> $H_v = 31.6 * 7 *10^{3}$

=> $H_v = 1.29 *10^{6} \ J$

Generally the overall amount of heat energy required is

$H_t = H + H_v$

=> $H_t = 7.8 *10^{4} + 1.29 *10^{6}$

=> $H_t = 1.37 *10^{6} \ J$

4 0

2 years ago

At 5000-kg freight car runs into 10000-kg freight car at rest. they couple upon collision and move with a speed of 2 m/s. what w

aliina [53]

Solution for the problem is:

Total momentum before collision is always equal to total momentum after collision. So note that:
Momentum of car A = 5000 x Xm/s
Momentum of car A + B = 15,000 x 2m/s

So combining the two, will give us the equation:
15,000/5,000 = 3
3 x 2 =6m/s

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2 years ago

The colored lines in the figure represent paths taken by different people walking around in a city. Assume that each city block

jarptica [38.1K]

Answer: 592.37m

Explanation:

Person D is the blue line.

The total displacement is equal to the difference between the final position and the initial position, if the initial position is (0,0) we have that he first goes down two blocks, then right 6 blocks. then up 4 blocks, then left 1 block.

Now i will considerate that the positive x-axis is to the right and the positive y-axis is upwards.

Then the new position will be, if B is a block:

P =(6*B - 1*B, -2*B + 4*B) = (5*B, 2*B)

And we know that B = 110m

P = (550m, 220m)

Now, then the displacement will be equal to the magnitude of our vector, (because the difference between P and the initial position is equal to P, as the initial position is (0,0)) this is:

P = √(550^2 + 220^2) = 592.37m

4 0

2 years ago

A fighter jet is catapulted off an aircraft carrier from rest to 75 m/s. If the aircraft carrier deck is 100 m long, what is the

egoroff_w [7]

The acceleration of the jet is $28.1 m/s^2$

Explanation:

Since the motion of the jet is a uniformly accelerated motion, we can use the following suvat equation:

$v^2-u^2=2as$

where

v is the final velocity

u is the initial velocity

a is the acceleration

s is the displacement

For the jet in this problem, we have

u = 0

v = 75 m/s

s = 100 m

Solving for a, we find the acceleration:

$a=\frac{v^2-u^2}{2s}=\frac{75^2-0}{2(100)}=28.1 m/s^2$

Learn more about acceleration:

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2 years ago

In the Netherlands, there is an annual ice-skating race called the "Tour of the Eleven Towns." The total distar.rce of the cours

rjkz [21]

Answer:

a) The average speed of the record race is 35.2 km/h

b) The time it will take to cover the first half is 2h 42 min

Explanation:

a) The average speed of the record race is calculated dividing the total distance over time:

v = distance/ time

So let´s write the time in hours:

if 60 s is 1 min, then 37 s will be (37 s · 1 min/60 s) 0.62 min.

If 60 min is 1 h, then 40.62 min will be (40.62 min · 1 h/60 min) 0.68 h

Then, the record time is 5.68 h

The average speed will be:

v = 2.00 × 10² km / 5.68 h = 35.2 km/h

b) Now we have the speed and the distance and have to find the time it will take the skater to cover that distance:

The speed will be:

v = 1.05v = 1.05 · 35.2 km/h = 37.0 km/h

The distance will be:

2.00 × 10² km /2 = 1.00 × 10² km

Then:

v = distance/ time

time = distance /v = 1.00 × 10² km / 37.0 km/h = 2.70 h

If 1 h is 60 min, 0.70 h will be (0.70 h · 60 min/h) 42 min.

The time it will take to cover the first half is 2h 42 min

3 0

2 years ago