<h2><u>Full Question:</u></h2>
Nathan drops marbles down two ramps that have different lengths. It takes the marbles 10 seconds to reach the bottom of both ramps.Which statement is TRUE?
answer choices
Marble 1 has a faster speed than Marble 2.
Marble 2 has a faster speed than Marble 1.
Both the marbles travel at the same speed.
There is not enough data to compare the speeds of marbles.
<h2><u>Answer:</u></h2>
Marble 2 has a faster speed than Marble 1.
Option B.
<h3><u>Explanation:</u></h3>
The speed is defined as the distance covered per unit time. Here in the question, 2 balls cover equal distances in same time.
Time taken by the ball = 10 seconds.
Distance covered by 1st ball = 20 cm.
Distance covered by 2nd ball = 3cm.
So speed of the 1st ball = 2cm/sec.
Speed of the 2nd ball = 3 cm /sec.
So,it's very much evident that speed of 2nd Marble is much higher than the speed of the 1st marble.
The oldest way ... the way we've been using as long as we've been
walking on the Earth ... has been to use plants. Plants sit out in the
sun all day, capturing its energy and using it to make chemical compounds.
Then we come along, cut the plants down, and eat them. Our bodies
rip the chemical compounds apart and suck the solar energy out of them,
and then we use the energy to walk around, sing, and play video games.
Another way to capture the sun's energy is to build a dam across a creek
or a river, so that the water can't flow past it. You see, it was the sun's
energy that evaporated the water from the ocean and lifted it high into
the sky, giving it a lot of potential energy. The rain falls on high ground,
up in the mountains, so the water still has most of that potential energy
as it drizzles down the river to the ocean. If we catch it on its way, we
can use some of that potential energy to turn wheels, grind our grain,
turn our hydroelectric turbines to get electrical energy ... all kinds of jobs.
A modern, recent new way to capture some of the sun's energy is to use
photovoltaic cells. Those are the flat blue things that you see on roofs
everywhere. When the sun shines on them, they convert some of its
energy into electrical energy. We use some of what they produce, and
we store the rest in giant batteries, to use when the sun is not there.
Although the semi truck certainly has a larger mass, it is not in motion and therefore does not have any momentum. The bicycle however has both mass and velocity and therefore has the larger momentum of the pair.
Answer:
Explanation:
Given:
Steam Mass rate, ms = 1.5 kg/min
= 1.5 kg/min × 1 min/60 sec
= 0.025 kg/s
Air Mass rate, ma = 100 kg/min
= 100 kg/min × 1 min/60 sec
= 1.67 kg/s
A.
Extracting the specific enthalpy and temperature values from property table of “Saturated water – Pressure table” which corresponds to temperature at 0.07 MPa.
xf, quality = 0.9.
Tsat = 89.9°C
hf = 376.57 kJ/kg
hfg = 2283.38 kJ/kg
Using the equation for specific enthalpy,
hi = hf + (hfg × xf)
= 376.57 + (2283.38 × 0.9)
= 2431.552 kJ/kg
The specific enthalpy of the outlet, h2 = hf
= 376.57 kJ/kg
B.
Rate of enthalpy (heat exchange), Q = mass rate, ms × change in specific enthalpy
= ms × (hi - h2)
= 0.025 × (2431.552 - 376.57)
= 0.025 × 2055.042
= 51.37455 kW
= 51.38 kW.
Answer:
(a) 
(b) P = 0.816 Watt
Explanation:
(a)
The power radiated from a black body is given by Stefan Boltzman Law:
where,
P = Energy Radiated per Second = ?
σ = stefan boltzman constant = 5.67 x 10⁻⁸ W/m².K⁴
T = Absolute Temperature
So the ratio of power at 250 K to the power at 2000 K is given as:
(b)
Now, for 90% radiator blackbody at 2000 K:
<u>P = 0.816 Watt</u>
