1) Should I take vitamin D supplements in the winter?

A light beam is directed parallel to the axis of a hollow cylindrical tube. When the tube contains only air, the light takes 8.7

mylen [45]

Answer:

1.208

Explanation:

L = Length of tube

c = Speed of light in air

v = Speed of light in jelly

Time taken by light in tube

$\dfrac{L}{c}=8.72$

Time taken when jelly is present

$\dfrac{L}{v}=8.72+1.82\\\Rightarrow \dfrac{L}{v}=10.54\ ns$

Dividing the above equations we get

$\dfrac{v}{c}=\dfrac{8.72}{10.54}\\\Rightarrow \dfrac{c}{v}=\dfrac{10.54}{8.72}\\\Rightarrow n=1.208$

The refractive index of the jelly is 1.208

4 0

3 years ago

Two frisky grasshoppers collide in midair at the top of their respective trajectories and grab onto each other, holding tight th

Svetlanka [38]

Answer:

The decrease in Kinetic energy is 0.0107 Joules

Explanation:

Given

Mass of grasshoppers

Let m1 = Mass of grasshopper 1

Let m2 = Mass of grasshopper 2

Let u1 = initial speed of grasshopper 1

Let u2 = initial speed of grasshopper 2

m1 = 250g = 0.25kg

m2 = 130g = 0.13kg

u1 = 15cm/s = 0.15m/s

u2 = 65cm/s = 0.65m/s

First, we calculate the final velocity of the grasshoppers after collision using conservation of momentum.

Using

m1u1 + m2u2 = (m1 + m2) * v

Where v = final velocity

By substituton

0.25 * 0.15 + 0.13 * 0.65 = (0.25 + 0.13) * v

0.0375 + 0.0845 = 380v

0.122 = 0.38v

Make v the subject of formula

v = 0.122/0.38

v = 0.321 m/s

Calculating the Kinetic energies before and after impact.

Before collision;

KE = ½m1u1²+ ½m2u2²

KE = ½(m1u1² + m2u2²)

By substituton;

KE = ½(0.25 * 0.15² + 0.13 * 0.65²)

KE = 0.030275J

After collision:

KE = ½(m1+m2)v²

KE = ½(0.25 + 0.13) * 0.321²

KE = 0.01957779 J

Change in kinetic energy = ∆KE

∆KE = 0.030275J - 0.01957779J

∆KE = 0.01069721J

∆KE = 0.0107 J --- Approximately

Hence the decrease in Kinetic energy is 0.0107 Joules

7 0

3 years ago

The gravitational force between a satellite and Earth’s moon is 324 N. The mass of the moon is 7.3 × 1022 kg.

tiny-mole [99]

450 kg is your answer middle school physic

8 0

4 years ago

Read 2 more answers

The filament of a 240 V, 100 W electric lamp heats up from room temperature to its operating temperature. As it heats up, its re

Xelga [282]

We need to use the formula P = IV, where P is the power, I is the current and V is the voltage.
When we substitute our values in, we get:
100 = 240I, and so I = 0.42 Amps
Now, we have to work out the Resistance in the circuit at the operating temperature.

We do this using the formula V = IR
240 = (100/240) x R, and we get R = 576 Ohms

Since the resistance has gone up by a factor of 16, all we have to do now is to divide this answer by 16 to get the resistance at room temperature.

576/16 = 36 Ohms

Hope I helped!! xx

3 0

3 years ago

Read 2 more answers

A spherical helium filled balloon (B) with a hanging passenger cage being held by a single vertical cable (C) attached to Earth

Gre4nikov [31]

Answer:

The tension is $T = 4326.7 \ N$