Explain why an ordinary bar magnet doesn’t rotate and align itself with Earth’s magnetic field when you place it on a table.

The graph below shows the speed of a car as it drives along a racetrack.

nordsb [41]

Answer:

Average speed = distance/time

From 1 to 9 seconds:

Distance covered = 1 - 0.2 = 0.8 km

Time = 9 - 1 = 8 sec

Average speed = 0.8 km / 8 sec

Average speed = 0.1 km/s .

The average speed for the whole test is 1.6 km / 20 sec = 0.08 km/sec. A graph of speed vs time would average out as a horizontal line at 0.08 km/sec from 1 sec to 21 sec. The area under it would be (0.08 km/s) x (20 sec) = 1.6 km.

Surprise surprise ! The area under a speed/time graph is the distance covered during that time !

In closing, I want to express my gratitude for the gracious bounty of 3 points with which I have been showered. Moreover, the green breadcrust and tepid cloudy water have also been refreshing.

Explanation:

4 0

3 years ago

You have an electrically neutral toy that you divide into two pieces. You notice that at least one of those pieces has an electr

musickatia [10]

Answer:

Attract

Explanation:

According to the properties of charge, the bodies having unlike charges attract each other and the bodies having like charges repel each other.

As the toy is initially electrically neutral, so as it is divided into two pieces, then according to the conservation of charge, the one piece having positive charge and the other piece having negative charge. As they are unlike charges so they attract each other.

8 0

4 years ago

A spring loaded toy shoots straight upward with a velocity of 4.5 m/s. Determine the maximum height it reaches. Determine the ti

Angelina_Jolie [31]

Recall that

${v_y}^2-{v_{0y}}^2=2a_y(y-y_0)$

At its maximum height $y_{\mathrm{max}}$ , the toy will have 0 vertical velocity, so that

$-\left(4.5\,\dfrac{\mathrm m}{\mathrm s}\right)^2=2\left(-9.8\,\dfrac{\mathrm m}{\mathrm s^2}\right)y_{\mathrm{max}}$

$\implies y_{\mathrm{max}}=1.0\,\mathrm m$

For the toy to reach this maximum height, it takes time $t$ such that

$\dfrac{0+v_0}2t=y_{\mathrm{max}}\implies t=0.46\,\mathrm s$

which means it takes twice this time, i.e. $t=0.92\,\mathrm s$ , for the toy to reach its original position.

The velocity of the toy when it falls 1.0 m below its starting point is

${v_y}^2-\left(4.5\,\dfrac{\mathrm m}{\mathrm s}\right)^2=2\left(-9.8\,\dfrac{\mathrm m}{\mathrm s^2}\right)(0-1.0\,\mathrm m)$

$\implies{v_y}^2=39.85\,\dfrac{\mathrm m^2}{\mathrm s^2}$

$\implies v_y=-6.4\,\dfrac{\mathrm m}{\mathrm s}$

where we took the negative square root because we expect the toy to be moving in the downward direction.

6 0

3 years ago

Water pressure in a lake is greater __________. a. at the bottom b. at the surface c. at any point, for pressure is the same d.

sweet-ann [11.9K]

Answer:

The correct answer a

Explanation:

In the fluid pressure is a measure of force per unit area, in this case force is the weight of the fluid that increases as we descend. Therefore, the pressure increases with the depth of the fluid.

The correct answer a

7 0

3 years ago

Read 2 more answers

Since many wavelengths of light are measured in nanometers, it's useful to know that planck's constant (h) multiplied with the s

MrRa [10]

Answer:

E = h f and since f = c / λ we have E = h c / λ

Thus λ = h c / E

Also, 1 ev = 1.6E-19 C

λ = 6.63E-34 * 3.0E8 / (1.6 * 1.6E-19)

λ = 6.63 * 3.0 / (1.6 * 1.6) * E-7

λ = 7.77E-7 = 777 nanometers

(B) is correct

4 0

2 years ago