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2 years ago

A professor determined the relationship between the time spent studying (in hours) and performance on an exam.

1 answer:

3 0

Lets write again formula for determening Ann's performance.

P = 70.443 + 4,885*t

where t is in hours. This is equation with P(t) which means that P only depends on variable t. If we express t=2.6 in formula we will find her expected performance.

P = 83.144

Now, since it says that she scored 16 points less than expected we need to find value of P-16

P - 16 = 67.144

After round we get that the answer is 67

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A ball on the end of a rope is moving in a vertical circle near the surface of the earth. Point A is at the top of the circle; C

mrs_skeptik [129]

Answer:

Tension in the string will increase

Explanation:

As we know that tension in the string at any angle with the vertical is given as

$T - mgcos\theta = m\omega^2 R$

now we have

$T = mgcos\theta + m\omega^2 R$

also we know that

angular speed of the stone is directly depending on the time period of the motion

so it is given as

$\omega = \frac{2\pi}{T}$

since the frequency of the revolution is increased from n = 1 rev/s to 2 rev/s

so the angular speed would be doubled

So here we can say that

tension in the string will increase when we will increase the frequency of revolution.

3 0

1 year ago

A glass beaker of unknown mass contains of water. The system absorbs of heat and the temperature rises as a result. What is the

kakasveta [241]

From the information provided in the question, the mass of the beaker is 144.4 g.

From the information provided in the complete question;

volume of water = 74 mL

Mass of water = 74 g

specific heat of glass = 0.18 cal/g ∙ °C

specific heat of water = 1.0 cal/g ∙ C°

Mass of glass = x g

Total heat gained by the system = 2000.0cal

Temperature rise = 20.0°C

Heat gained by system = Heat gained by glass + Heat gained by water

Heat gained by glass = x × 0.18 × 20

Heat gained by water = 74 × 1.0 × 20

Hence;

2000 = (x × 0.18 × 20) + ( 74 × 1.0 × 20)

2000 - 1480 = (x × 0.18 × 20)

x = 520/3.6

x = 144.4 g

Missing parts;

A glass beaker of unknown mass contains 74.0 ml of water. The system absorbs 2000.0cal of heat and the temperature rises 20.0°C as a result. What is the mass of the beaker? The specific heat of glass is 0.18

cal/g °C, and that of water is 1.0 cal/g °C.

Learn more: brainly.com/question/1446583

3 0

1 year ago

What is the momentum of a 533 kg blimp moving east at +75 m/s

mylen [45]

Answer:

39975kgm/s due east

Explanation:

Given parameters:

Mass of the blimp = 533kg

Velocity = +75m/s due east

Unknown:

Momentum of the body = ?

Solution:

The momentum of a body is the amount of motion it posses.

Momentum is the product of mass and velocity;

Momentum = mass x velocity

Insert the parameters and solve;

Momentum = 533 x 75 = 39975kgm/s

The momentum of the body is 39975kgm/s due east

7 0

1 year ago

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 $c_w = 4.18 J/g^oC$

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

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

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

As a car drives with its tires rolling freely without any slippage, the type of friction acting between the tires and the road i

Kitty [74]

Answer:

B. Kinetic friction

Explanation:

This is definitely the correct answer because kinetic friction acts when an object is in motion and it allows the object to move without slipping, etc

ALSO, PLEASE DO MARK ME AS BRAINLIEST UWU 

Bonne journée ;) 

6 0

1 year ago

Read 2 more answers