All categories

3 years ago

You drop a rock down a well that is 11.5 m deep.How long does it take the rock to hit the bottom of the well ?

1 answer:

4 0

The acceleration of gravity depends on the distance from
the center of the Earth. We use 9.8 m/s² for any place that's
on the Earth's surface, or reasonably close. The 11.5 meters
down into the well certainly qualifies.

The formula we want is:

Distance of fall = (1/2) · (acceleration) · (time)²

      11.5 m = (1/2) (9.8 m/s²) (time)²

Divide each side
by 4.9 m/s² : (11.5m) / (4.9 m/s²) = time²

   2.347 sec² = time²

   time = √(2.347 sec²) =   1.53 seconds .

You might be interested in

What’s the difference between expressed/implied powers, concurrent powers, and reserved powers?.

Lisa [10]

Answer:

A reserved power is a power specifically reserved to the states. Powers include setting up local governments and determining the speed limit. A concurrent power is a power that is given to both the states and the federal government.

Explanation:

3 0

3 years ago

A coil has N turns enclosing an area of A. In a physics laboratory experiment, the coil is rotated during the time interval delt

zmey [24]

Answer:

a) Magnetic flux before the plane is rotated = (BA) Wb

b) Magnetic flux after the plane is rotated = 0 Wb

c) Magnitude of the average induced emf =

(NBA)/Δt

Explanation:

The magnetic flux is given as

Φ = BA cos θ

where B = magnetic field strength

A = Cross sectional Area of the loop enclosed

θ = the angle in the equation above is between the line normal to plane (NOT the plane itself!) and the magnetic field.

a) Given that the position of the plane of each turn is perpendicular to Earth's magnetic field before being rotated.

Before the plane is rotated, θ = 0°

Φ = BA cos θ = BA cos 0° = BA

b) Given that the position of the plane of each turn is parallel to Earth's magnetic field after being rotated.

After the plane is rotated, θ = 90°

Φ = BA cos θ = BA cos 90° = 0

c) According to the Faraday's law of electromagnetic induction,

E = - N (ΔΦ/Δt) (minus sign to indicate that the direction of the induced emf is opposite the direction of the change of magnetic flux)

ΔΦ = (final Φ) - (initial Φ) = (0 - BA) = - BA

E = - N (- BA)/Δt

E = (NBA)/Δt

Hope this Helps!!!

8 0

3 years ago

Read 2 more answers

Sorry I’ve just been having trouble with this question

tiny-mole [99]

Answer:

68.8 N 13.8°N of W

Explanation:

F₁ is 50 N 30°N of W. The terminal angle is 150°.

F₂ is 25 N 20°S of W. The terminal angle is -160°.

Graphically, you can add the vectors using head-to-tail method. Move F₂ so that the tail of the vector is at the head of F₁. The resultant vector will be from the tail of F₁ to the head of F₂.

Algebraically, find the x and y components of each vector.

F₁ₓ = 50 N cos(150°) = -43.3 N

F₁ᵧ = 50 N sin(150°) = 25 N

F₂ₓ = 25 N cos(-160°) = -23.5 N

F₂ᵧ = 25 N sin(-160°) = -8.6 N

The x and y components of the resultant vector are the sums:

Fₓ = -43.3 N + -23.5 N = -66.8 N

Fᵧ = 25 N + -8.6 N = 16.4 N

The magnitude of the resultant force is:

F = √(Fₓ² + Fᵧ²)

F = √((-66.8 N)² + (16.4 N)²)

F = 68.8 N

The direction of the resultant force is:

θ = tan⁻¹(Fᵧ / Fₓ)

θ = tan⁻¹(16.4 N / -66.8 N)

θ = 166.2°

θ = 13.8°N of W

6 0

3 years ago

A coil of 1,000 turns encloses an area of 85 cm^2. It is rotated in 0.090 s from a position where its plane is perpendicular to

Maurinko [17]

Answer:

The average emf induced in the coil is $5.6\times10^{-3}\ mV$ .

Explanation:

Given that,

Number of turns = 1000 turns

Area = 85 cm²

Time = 0.090 s

Its plane is perpendicular to Earth's magnetic field.

Angle = 0°

Magnetic strength $B=6.0\times10^{-5}\ T$

We need to calculate the magnetic flux

Using formula of magnetic flux

$\phi=BA\cos\theta$

Put the value into the formula

$\phi=6.0\times10^{-5}\times85\times10^{-4}\times\cos0^{\circ}$

$\phi =6.0\times10^{-5}\times85\times10^{-4}\times1$

$\phi=5.1\times10^{-7}\ Wb$

We need to calculate the average emf induced in the coil

$\epsilon=\dfrac{d\phi}{dt}$

Put the value into the formula

$\epsilon=\dfrac{5.1\times10^{-7}}{0.090}$

$\epsilon=0.0000056\ N$

$\epsilon =5.6\times10^{-3}\ mV$

Hence, The average emf induced in the coil is $5.6\times10^{-3}\ mV$ .

3 0

3 years ago

If you increase the charge on a parallel-plate capacitor from 3 mu or micro CC to 9 mu or micro CC and increase the plate separa

aliya0001 [1]

Explanation:

The energy stored in a capacitor is given by

$U = \dfrac{1}{2}QV = \dfrac{Q^2}{2C}$

In the case of a parallel plate capacitor, the capacitance C is given by

$C = \dfrac{\epsilon_0A}{d}$

so we can rewrite the expression for the energy as

$U = \dfrac{Q^2d}{2\epsilon_0 A}$

Increasing the charge from $3\:\mu\text{C}\:\text{to}\:9\:\mu\text{C}$ means that you're tripling the charge. The same thing is true when you increase the distance from 1.8 mm to 5.4 mm, i.e., you triple the separation distance. So the new energy U' is given by

$U' = \dfrac{Q'^2d'}{2\epsilon_0 A}$

$\:\:\:\:\:\:= \dfrac{(3Q)^2(3d)}{2\epsilon_0 A}$

$\:\:\:\:\:\:= 27\left(\dfrac{Q^2d}{2\epsilon_0 A}\right)$

$\:\:\:\:\:\:= 27U$

As we can see, tripling both the charge and the separation distance result in the 27-fold increase in its stored energy U.

7 0

3 years ago