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3 years ago

What is the new current?

Physics

1 answer:

nikdorinn [45]3 years ago

3 0

Voltage = current x resistance
since R is doubled, current must reduce by half.
So,
new current = 120/2 = 60mA

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A hot air balloon is traveling vertically upward at a constant speed of 4.5 m/s. When it is 28 m above the ground, a package is

ella [17]

Answer:

1.97 seconds

Explanation:

t = Time taken

u = Initial velocity

v = Final velocity

s = Displacement

a = Acceleration due to gravity = 9.8 m/s²

$s=ut+\frac{1}{2}at^2\\\Rightarrow 21=4.5t+\frac{1}{2}\times -9.8\times t^2\\\Rightarrow 21=-4.5t-4.9t^2\\\Rightarrow 4.9t^2+4.5t-28=0\\\Rightarrow 49t^2+45t-280=0$

Solving the above equation we get

$t=\frac{-45+\sqrt{45^2-4\cdot \:49\left(-280\right)}}{2\cdot \:49}, \frac{-45-\sqrt{45^2-4\cdot \:49\left(-280\right)}}{2\cdot \:49}\\\Rightarrow t=1.97, -2.89$

So, the time the package was in the air is 1.97 seconds

3 0

3 years ago

J-s. If your 1400-kg car is parked in an 8.54-m-long garage, what is the uncertainty in its velocity? cm/s the tolerance is +/-2

IgorC [24]

Answer:

$\Delta v = 4.41 \times 10^{-37} cm/s$

Explanation:

As per Heisenberg's uncertainty principle we know that

$\Delta P \times \Delta x = \frac{h}{4\pi}$

so here we have

$\Delta P = m\Delta v$

$\Delta x = 8.54 m$

now from above equation we have

$m\Delta v \times (8.54) = \frac{h}{4\pi}$

$1400(\Delta v) \times (8.54) = \frac{6.626 \times 10^{-34}}{4\pi}$

$\Delta v = 4.41 \times 10^{-39} m/s$

$\Delta v = 4.41 \times 10^{-37} cm/s$

8 0

3 years ago

The modulus of elasticity for a ceramic material having 4.7 vol% porosity is 317 GPa. (a) Calculate the modulus of elasticity (i

elena-s [515]

Answer:

The answer is below

Explanation:

a) Given that the modulus of elasticity (E) = 317 GPa, to find the modulus of elasticity (in GPa) for the nonporous material ( $E_o$ ), we use the formula:

$E_0=\frac{E}{1-1.9P+0.9P^2}\\\\where\ P=4.7\%=0.047,hence:\\\\ E_0=\frac{317}{1-1.9(0.047)+0.9(0.047)^2}\\\\E_0=347.3\ GPa$

b) If the porosity P = 11.1%, then the modulus of elasticity is:

$E=E_0(1-1.9P+0.9P^2)=347.3(1-1.9(0.111)+0.9(0.111)^2)=278\ GPa$

5 0

3 years ago

A soccer ball is kicked with a speed of 22m/s at an angle of 35.0º above the horizontal. If the ball lands at the same level fro

Lisa [10]

Answer:

2.57 seconds

Explanation:

The motion of the ball on the two axis is;

x(t) = Vo Cos θt

y(t) = h + Vo sin θt - 1/2gt²

Where; h is the initial height from which the ball was thrown.

Vo is the initial speed of the ball, 22 m/s , θ is the angle, 35° and g is the gravitational acceleration, 9.81 m/s²

We want to find the time t at which y(t) = h

Therefore;

y(t) = h + Vo sin θt - 1/2gt²

Whose solutions are, t = 0, at the beginning of the motion, and

t = 2 Vo sinθ/g

= (2 × 22 × sin 35°)/9.81

= 2.57 seconds

6 0

3 years ago

HELP DUE 3 MINUTESSSSD

Delvig [45]

Answer:

Break down small pebbles and sediments, like sand

Break down large rocks like mountains

Explanation:

6 0

3 years ago