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gavmur [86]
3 years ago
7

A typical student listening attentively to a physics lecture has a heat output of 100 w . how much heat energy does a class of 1

70 physics students release into a lecture hall over the course of a 50 min lecture?
Physics
1 answer:
nexus9112 [7]3 years ago
7 0

Since each student emits 100 W, so 170 students will emit:

total heat = 100 W * 170 = 17,000 W

 

Convert minutes to seconds:

time = 50 min * (60 s / min) = 3000 s

 

The energy is therefore:

E = 17,000 W * 3000 s

<span>E = 51 x 10^6 J = 51 MJ</span>

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A boy of mass, m weights 895 N. What is his mass, m?
Ksju [112]

Answer:

91.3 kg

Explanation:

weight = m*g

m: mass

g: gravity = 9.8 or 10 (depends on what your instructor tells you to use)

mass = w/g

895/9.8 = 91.3 KG

6 0
3 years ago
Determine the gravitational potential energy, in kJ, of 3 m3 of liquid water at an elevation of 40 m above the surface of Earth.
melomori [17]

Explanation:

We will calculate the gravitational potential energy as follows.

                 P.E_{1} = mgz_{1}

       P.E_{1} = (\rho V)gz_{1}    

                    = 1000 kg/m^{3} \times 3 m^{3} \times 9.7 \times 40 m

                    = 1164000 J

or,                = 1164 kJ         (as 1 kJ = 1000 J)

Now, we will calculate the change in potential energy as follows.

             \Delta P.E = mg(z_{2} - z_{1})

                         = \rho \times V \times g (z_{2} - z_{1})

                         = 1000 \times 3 \times 9.7 (10 - 40)m

                         = -873000 J

or,                      = -873 kJ

Thus, we can conclude that change in  gravitational potential energy is -873 kJ.

4 0
3 years ago
Two objects were lifted by a machine. One object had a mass of 5000 kg, and was lifted at a speed of 2 m/sec. The other had a ma
Leokris [45]
Equation for ke = 1/2mv^2
1) ke = 1/2 x 5000 x (2x2)
= 10,000J
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So Object 2 has more Kinetic Energy
3 0
3 years ago
Classify each possible hypothesis about a medicinal aloe vera plant as falsifiable or non-falsifiable.
pychu [463]

Answer:

Aloe vera is a succulent plant species ( with fleshy water storing tissue) belonging to the genus Aloe.

It is used in many products ( including beverages, cosmetic products as gel, medicinal ointments). Its juice is quite bitter in taste. It is known to be the best skin moisturizer and can be used for healing wounds by enhancing the renewal of damaged cells. It is also used as an anticarcinogen, thus reduces the chances of cancer.

Thus, the given hypothesis can be classified as  falsifiable ( which is proven wrong) or non-falsifiable ( which is proven right) in the following way-

Falsifiable-

Aloe vera juice tastes  better than carrot juice.

Non Falsifiable-

Aloe vera gel is the best  natural skin moisturizer.

Aloe vera gel can heal  wounds by boosting  cell renewal.

Drinking aloe juice can  reduce the risk of lung  cancer.

7 0
3 years ago
A cube with sides of length 2cm has a mass of 7.36g . calculate the density of the cube
kondor19780726 [428]
Density = 7.36 grams ÷ (2 cm × 2 cm × 2cm) = 0.92 g/cm^3

7 0
3 years ago
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