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4 years ago

Why does your body feels like it is being pushed back when the car starts back up again

1 answer:

5 0

The acceleration due to gravity is not due to the Earth's motion through space. It is due to the gravitational force pulling you towards the center of mass of the Earth. The ground pushes back, and what you feel is your weight. This is the same as what you feel in an accelerating car.

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A car owner forgets to turn off the headlights of his car while it is parked in his garage. If the 12.0-V battery in his car is

luda_lava [24]

Answer:

It will take time=7.963 hours to completely discharge

Explanation:

The energy available in the battery is:

Energy stored=Power×Time

Energy stored=(ΔV)I×t

Energy stored=(12.0V×43.0A.h)

Energy stored=516 W.h

The two headlights together consume a total power of:

$P=2*32.4W\\P=64.8W$

So the time required to completely discharge is:

$time=\frac{Energy.stored}{P}\\ time=\frac{516 W.h}{64.8W}\\ time=7.963hours$

It will take time=7.963 hours to completely discharge

3 0

4 years ago

Read 2 more answers

A mass of air occupies a volume of 5.7 L at a pressure of 0.52 atm. What is the new pressure if the same mass of air at the same

Nikolay [14]

Apply Boyle's law:

PV = const.

P = pressure, V = volume, the product of P and V must stay constant

Our initial P and V values are:

P = 0.52atm, V = 5.7L

Our final P and V values are:

P = ?, V = 2.0L

Set the products of each set of PV values equal to each other and solve for the final P:

P(2.0) = 0.52(5.7)

P = 1.48atm

5 0

3 years ago

A 6.0 kg block, starting from rest, slides down a frictionless incline of length 2.0 m. When it arrives at the bottom of the inc

erica [24]

Since
Vf^2 = 2*a*S 
Given S=3.6m, thus 
a = Vf^2/(2*3.6) 
a = Vf^2/7.2 

Let d be the distance along the slope at which the velocity is 0.5Vf, then 
(0.5Vf)^2 = 2*a*d 
or 
d = (0.5*Vf)^2/(2*a) 
with a = Vf^2/7.2, we have 
d = 0.9 m

8 0

3 years ago

2. A string with a length of 0.9m that is fixed at both ends

aliina [53]

Answer:

2a.) Wavelength = 1.8 m

2b.) F = 66.67 Hz

3a.) Find the attached file

3b.) Wavelength = 0.6 m

Explanation:

Given that the

Length L = 0.9m

Wavelength (λ) = 2L/n

Where n = number of harmonic

If n = 1, then

Wavelength (λ) = 2L = 2 × 0.9 = 1.8 m

b.)

If waves travel at a speed of 120m/s on this string, what is the frequency

associated with the longest wave (first harmonic)?

Given that V = 120 m/s

V = Fλ

But λ = 2L, therefore,

F = V/2L

F = 120/1.8

F = 66.67 Hz

3. b.) If there are two node, the position will be in 3rd position which is 3rd harmonic

Using the same formula,

Wavelength (λ) = 2L/n

Where n = 3

Wavelength (λ) = 2 × 0.9/3

Wavelength (λ) = 0.6 m

3 0

3 years ago

A physics student with too much free time drops a watermelon from a roof of a building, hears the sound of the watermelon going

tatiyna

Answer:

28.6260196842 m

Explanation:

Let h be the height of the building

t = Time taken by the watermelon to fall to the ground

Time taken to hear the sound is 2.5 seconds

Time taken by the sound to travel the height of the cliff = 2.5-t

Speed of sound in air = 340 m/s

For the watermelon falling

$s=ut+\frac{1}{2}at^2\\\Rightarrow h=0t+\frac{1}{2}\times 9.81\times t^2\\\Rightarrow h=\frac{1}{2}\times 9.81\times t^2$

For the sound

Distance = Speed × Time

$\text{Distance}=340\times (2.5-t)$

Here, distance traveled by the stone and sound is equal

$\frac{1}{2}\times 9.81\times t^2=340\times (2.5-t)\\\Rightarrow 4.905t^2=340\times (2.5-t)\\\Rightarrow t^2=\frac{340}{4.905}(2.5-t)\\\Rightarrow t^2+69.3170234455t-173.292558614=0$

$t=\frac{-69.31702\dots +\sqrt{69.31702\dots ^2-4\cdot \:1\cdot \left(-173.29255\dots \right)}}{2\cdot \:1},\:t=\frac{-69.31702\dots -\sqrt{69.31702\dots ^2-4\cdot \:1\cdot \left(-173.29255\dots \right)}}{2\cdot \:1}\\\Rightarrow t=2.4158\ s\ or\ -71\ seconds$

The time taken to fall down is 2.4158 seconds

$h=\frac{1}{2}\times 9.81\times 2.4158^2=28.6260196842\ m$

Height of the buidling is 28.6260196842 m

7 0

4 years ago