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3 years ago

What statements correctly describe theories

Physics

1 answer:

elixir [45]3 years ago

8 0

Theories result from several repeated experiments.

Theories explain observations and hypotheses.

Theories may be revised over time.

Explanation:

Scientific theories are purely explanations into an observation and hypothesis. The are general binding explanations that have been developed from several tests.

Theories are products of different stages of experiments in their own regard.
For a theory to be accepted by the scientific community, its hypothesis statement must be:

Testable
Repeated
Falsifiable

Based on new evidence, a theory may be revised with time. One of such is the Dalton's atomic theory with a modern atomic theory version now.

Learn more:

Experiments brainly.com/question/5096428

#learnwithBrainly

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When jumping straight down, you can be seriously injured if you land stiff-legged. One way to avoid injury is to bend your knees

dolphi86 [110]

Answer:

a) 1.725*10^5 N

b) 3.83*10^3 N

c) i) 173.24 kN

c) ii) 4.57 kN

Explanation:

See the attachment for calculations

6 0

3 years ago

An autotransformer is used to reduce the voltage of a 100-kilovolt amp, 480-volt secondary of an isolated type transformer, to s

tigry1 [53]

Answer:

42KVA

Explanation:

Given data

High Voltage (HV)= 480V

Low Voltage (LV)= 277V

Fo find

Size of transformer=?

Solution

To find the size of transformer here we use the co-ratio.The Co-ratio is given as:

Co-Ratio= (HV - LV)/HV

where

HV is High Voltage

LV is Low Voltage

Now put the values we get

Co- Ratio=(480-277)/480=.42

So the size of transformer is 42KVA

5 0

3 years ago

Car A (mass 1100 kg) is stopped at a traffic light when it is rearended by car B(mass 1400 kg). Both cars then slide with locke

viva [34]

Answer:

Part a)

$v_a = 3.94 m/s$

Part b)

$v_b = 3.35 m/s$

Part C)

$v_b = 6.44 m/s$

Part d)

Due to large magnitude of friction between road and the car the momentum conservation may not be valid here as momentum conservation is valid only when external force on the system is zero.

Explanation:

Part a)

As we know that car A moves by distance 6.1 m after collision under the frictional force

so the deceleration due to friction is given as

$a = -\frac{F_f}{m}$

$a = -\frac{\mu mg}{m}$

$a = - \mu g$

now we will have

$v_f^2 - v_i^2 = 2ad$

$0 - v_i^2 = 2(-\mu g)(6.1)$

$v_a = \sqrt{(2(0.13)(9.81)(6.1)}$

$v_a = 3.94 m/s$

Part b)

Similarly for car B the distance of stop is given as 4.4 m

so we will have

$v_b = \sqrt{2(0.13)(9.81)(4.4)}$

$v_b = 3.35 m/s$

Part C)

By momentum conservation we will have

$m_1v_{1i} = m_1v_{1f} + m_2v_{2f}$

$1400 v_b = 1100(3.94) + 1400(3.35)$

$v_b = 6.44 m/s$

Part d)

Due to large magnitude of friction between road and the car the momentum conservation may not be valid here as momentum conservation is valid only when external force on the system is zero.

3 0

3 years ago

Need help with this physics question!

Fynjy0 [20]

Answer:

omg i need help with the same answer lol

Explanation:

i wish i can help but i need help on this hehe

6 0

3 years ago

A 30 ohm resistor and a 20 ohm resistor are

Reptile [31]

The current that would pass through the 30 ohms resistor is 2 A.

<h3>What is electric current?</h3>

Electric current is the rate of flow of electric charge round a conductor.

To calculate the electric current that would pass through the 30 ohms resistor, we use the formula below

Formula:

I = V/Rt........... Equation 1

Where:

I = Electric current passing through the 30 ohms resistor
V = Voltage
Rt = Total or effective resistance of the resistors.

From the question,

Given:

V = 100 volts
Rt = (30+20) ohms (since both resistors are connected in series)

Rt = 50 ohms

Substitute these values into equation 1

I = 100/50
I = 2 A

Hence, The current that would pass through the 30 ohms resistor is 2 A.

Learn more about electric current here: brainly.com/question/1100341

8 0

3 years ago