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3 years ago

9. Pick the best example of Newton's Second Law in action.

Physics

1 answer:

madreJ [45]3 years ago

7 0

Answer:

A rocket taking off from earth which pushes gasses in one direction and the rocket in

the other

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A 5.45-g combustible sample is burned in a calorimeter. the heat generated changes the temperature of 555 g of water from 20.5°c

Y_Kistochka [10]

Given:
m = 555 g, the mass of water in the calorimeter
ΔT = 39.5 - 20.5 = 19 °C, temperature change
c = 4.18 J/(°C-g), specific heat of water

Assume that all generated heat goes into heating the water.
Then the energy released is
Q = mcΔT
= (555 g)*(4.18 J/(°C-g)*(19 °C)
= 44,078.1 J
= 44,100 J (approximately)

Answer: 44,100 J

3 0

3 years ago

A projectile, fired with unknown initial velocity, lands 20sec later on side of hill, 3000m away horizontally and 450m verticall

lorasvet [3.4K]

Explanation:

Given:

t = 20 seconds

x = 3000 m

y = 450 m

a) To find the vertical component of the initial velocity $v_{0y}$ , we can use the equation

$y = v_{0y}t - \frac{1}{2}gt^2$

Solving for $v_{0y}$ ,

$v_{0y} = \dfrac{y + \frac{1}{2}gt^2}{t}$

$\:\:\:\:\:\:\:=\dfrac{(450\:\text{m}) + \frac{1}{2}(9.8\:\text{m/s}^2)(20\:\text{s})^2}{(20\:\text{s})}$

$\:\:\:\:\:\:\:=120.5\:\text{m/s}$

b) We can solve for the horizontal component of the velocity $v_{0x}$ as

$x = v_{0x}t \Rightarrow v_{0x} = \dfrac{x}{t} = \dfrac{3000\:\text{m}}{20\:\text{s}}$

$v_{0x} = 150\:\text{m/s}$

4 0

3 years ago

In a shot-put competition, a shot moving at 15m/s has 450J of mechanical kinetic energy. What is the mass of the shot? Please he

Llana [10]

Answer:

Mass of shot (m) = 4 kg

Explanation:

Given:

Velocity (v) = 15 m/s

Mechanical kinetic energy (K.E) = 450 J

Find:

Mass of shot (m) = ?

Computation:

Mechanical kinetic energy (K.E) = 1/2mv²

Mechanical kinetic energy (K.E) = [1/2](m)(15)²

450 = [1/2](m)(15)²

900 = 225 m

Mass of shot (m) = 4 kg

5 0

3 years ago

Briefly explain how the eye works.

antiseptic1488 [7]

The eye works When light hits the retina (a light-sensitive layer of tissue at the back of the eye), special cells called photoreceptors turn the light into electrical signals. These electrical signals travel from the retina through the optic nerve to the brain. Then the brain turns the signals into the images you see.

5 0

3 years ago

Read 2 more answers

A particle leaves the origin with a speed of 2.1 times 106 m/s at 30 degrees to the positive x axis. It moves in a uniform elect

Verizon [17]

Answer:

-1449.69404 N/C

Explanation:

u = Velocity of particle = $2.1\times 10^6\ m/s$

$\theta$ = Angle = 30°

x = Distance = 1.5 cm

m = Mass of electron = $9.11\times 10^{-31}\ kg$

q = Charge of electron = $-1.6\times 10^{-19}\ C$

In the case of projectile motion

$x=utcosA\\\Rightarrow t=\dfrac{x}{ucosA}$

The force of on the particle will balance the Electric force

$ma=qE\\\Rightarrow a=\dfrac{qE}{m}$

Now

$y=utsin\theta-\dfrac{1}{2}at^2\\\Rightarrow y=utsin\theta-\dfrac{1}{2}\dfrac{qE}{m}t^2$

If y = 0

$0=utsin\theta-\dfrac{1}{2}\dfrac{qE}{m}t^2\\\Rightarrow utsin\theta=\dfrac{1}{2}\dfrac{qE}{m}t^2\\\Rightarrow t=\dfrac{2musin\theta}{qE}$

$\dfrac{x}{ucosA}=\dfrac{2musin\theta}{qE}\\\Rightarrow E=\dfrac{2mu^2sin\theta cos\theta}{xq}\\\Rightarrow E=\dfrac{2\times 9.11\times 10^{-31}\times (2.1\times 10^6)^2\times sin30\times cos30}{1.5\times 10^{-2}\times (-1.6\times 10^{-19})}\\\Rightarrow E=-1449.69404\ N/C$

The electric field is -1449.69404 N/C

8 0

3 years ago