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arsen [322]
3 years ago
8

Two groups wanted to determine which size of parachute, when released, fell to the ground the slowest. Each group's design and r

esults are shown in the table below.
Each group designed their parachutes as follows:
Design and Results by Group

Group 1
6 20 cm pieces of string
1 50 g package
24 cm round plastic parachute

Results
6 seconds
Group 2
6 20 cm pieces of string
1 50 g package
12 cm round plastic parachute

Results
3 seconds

Which of the following explains why this exercise represents a carefully designed experiment?

A.
They used the same mass of package in all the trials.
B.
They altered only one variable in their design and testing.
C.
They used the same materials when making each parachute.
D.
They confirmed that the smaller the parachute, the faster it falls.
Physics
1 answer:
ser-zykov [4K]3 years ago
3 0
The correct answer is B) They altered only one variable in their design and testing.
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At room temperature, good conductors of heat usually feel cool to the touch. This is because they conduct heat so quickly that w
sp2606 [1]

C. copper

Explanation:

Copper is the best conductor of heat from the given options. Plastic, wood and cotton are all poor conductors other wise known as insulators.

Metals are typically good conductors of heat.

  • they generally do not have a high specific heat capacity which implies that they get heated easily.
  • a good conductor allows heat to flow fast and it simultaneously loses heat readily too.
  • copper is a good conductor, when heat its perfectly allows heat to pass through
  • when heat is removed, it loses it very fast.

Learn more:

Conductors brainly.com/question/2500879

#learnwithbrainly

4 0
3 years ago
A coil with an inductance of 2.3 H and a resistance of 14 Ω is suddenly connected to an ideal battery with ε = 100 V. At 0.13 s
klemol [59]

Given Information:

Resistance = R = 14 Ω

Inductance = L = 2.3 H

voltage = V = 100 V

time = t = 0.13 s

Required Information:

(a) energy is being stored in the magnetic field

(b) thermal energy is appearing in the resistance

(c) energy is being delivered by the battery?

Answer:

(a) energy is being stored in the magnetic field ≈ 219 watts

(b) thermal energy is appearing in the resistance ≈ 267 watts

(c) energy is being delivered by the battery ≈ 481 watts

Explanation:

The energy stored in the inductor is given by

U = \frac{1}{2} Li^{2}

The rate at which the energy is being stored in the inductor is given by

\frac{dU}{dt} = Li\frac{di}{dt} \: \: \: \: eq. 1

The current through the RL circuit is given by

i = \frac{V}{R} (1-e^{-\frac{t}{ \tau} })

Where τ is the the time constant and is given by

\tau = \frac{L}{R}\\ \tau = \frac{2.3}{14}\\ \tau = 0.16

i = \frac{110}{14} (1-e^{-\frac{t}{ 0.16} })\\i = 7.86(1-e^{-6.25t})\\\frac{di}{dt} = 49.125e^{-6.25t}

Therefore, eq. 1 becomes

\frac{dU}{dt} = (2.3)(7.86(1-e^{-6.25t}))(49.125e^{-6.25t})

At t = 0.13 seconds

\frac{dU}{dt} = (2.3) (4.37) (21.8)\\\frac{dU}{dt} = 219.11 \: watts

(b) thermal energy is appearing in the resistance

The thermal energy is given by

P = i^{2}R\\P = (7.86(1-e^{-6.25t}))^{2} \cdot 14\\P = (4.37)^{2}\cdot 14\\P = 267.35 \: watts

(c) energy is being delivered by the battery?

The energy delivered by battery is

P = Vi\\P = 110\cdot 4.37\\P = 481 \: watts

4 0
3 years ago
A fin whale is swimming at the speed of 35 km/h how many hours will it take to swim 7 km
Aleks04 [339]

Answer:

0.2 hours

Explanation:

\frac{7}{35}  = 0.2

7 0
2 years ago
In order for a ball to move upward, the initial velocity of the ball must be greater than _____.
ch4aika [34]

Answer:

The answer is zero please Give me Brainly

Explanation:

5 0
2 years ago
A circuit has a 10 Ω resistor connected to a 1.5 V dry cell. What is the current that can flow in the circuit?
ludmilkaskok [199]

Here is the highly detailed, arcane, complex, technical form of Ohm's Law that is needed in order to answer this question  ===>  I = V / R  .

Current = (voltage) / (resistance)

Current = (1.5 V) / (10 Ω)

<em>Current = 0.15 Ampere</em>

8 0
3 years ago
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