A train is accelerating at a rate of 3 m/s2. If it's initial velocity is 30 m/s. What is its velocity after 60 seconds?

Light travelling in one material enters another material in which it travels faster. The light wave will:

Free_Kalibri [48]

The light will change its direction and bend away from the normal.

8 0

4 years ago

in a football game, the kicker kicks a football a horizontal distance of 43 yards if the ball lands 3.9 seconds later, what is t

erica [24]

Answer:

10s

Explanation:

7 0

3 years ago

A cube of water 10 cm on a side is placed in a microwave beam having Ea = 11 kV/m‘ The microwaves illuminate one faceofthe cube,

Shtirlitz [24]

Answer:

The time is 133.5 sec.

Explanation:

Given that,

One side of cube = 10 cm

Intensity of electric field = 11 kV/m

Suppose How long will it take to raise the water temperature by 41°C Assume that the water has no heat loss during this time.

We need to calculate the rate of energy transfer from the beam to the cube

Using formula of rate of energy

$P=(0.80)IA$

$P=0.80\times\dfrac{c\mu_{0}E^2}{2}\times A$

Put the value into the formula

$P=0.80\times\dfrac{3\times10^{8}\times8.85\times10^{-12}\times(1.1\times10^{4})^2}{2}\times(10\times10^{-2})^2$

$P=1285.02\ W$

We need to calculate the amount of heat

Using formula of heat

$E =mc\Delta T$

$E =\rho Vc\Delta T$

Put the value into the formula

$E=1000\times(0.10)^3\times4186\times41$

$E=171626\ J$

We need to calculate the time

Using formula of time

$t=\dfrac{E}{P}$

Put the value into the formula

$t=\dfrac{171626}{1285.02}$

$t=133.5\ sec$

Hence, The time is 133.5 sec.

3 0

4 years ago

The radius of a planet is 2400 km, and the acceleration due to gravity at its surface is 3.6 m/s2.

kiruha [24]

Answer:

$3.1\cdot10^{23}\:\mathrm{kg}$

Explanation:

We can use Newton's Universal Law of Gravitation to solve this problem:

$g_P=G\frac{m}{r^2}$ ., where $g_P$ is acceleration due to gravity at the planet's surface, $G$ is gravitational constant $6.67\cdot 10^{-11}$ , $m$ is the mass of the planet, and $r$ is the radius of the planet.

Since acceleration due to gravity is given as $m/s^2$ , our radius should be meters. Therefore, convert $2400$ kilometers to meters:

$2400\:\mathrm{km}=2,400,000\:\mathrm{m}$ .

Now plugging in our values, we get:

$3.6=6.67\cdot10^{-11}\frac{m}{(2,400,000)^2}$ ,

Solving for $m$ :

$m=\frac{2,400,000^2\cdot3.6}{6.67\cdot 10^{-11}},\\m=\fbox{$3.1\cdot10^{23}\:\mathrm{kg}$}$ .

6 0

3 years ago

Superman attempts to drink water through a very long vertical straw. With his great strength, he achieves maximum possible sucti

Stells [14]

Answer:

10.32874 m

Explanation:

$P_a$ = Atmospheric pressure = 101325 Pa

g = Acceleration due to gravity = 9.81 m/s²

h = Height of water

$\rho$ = Density of water = 1000 kg/m³

If the walls of the tube do not collapse that means that maximum pressure inside will be the atmospheric pressure

Atmospheric pressure is given by

$P_a=\rho gh\\\Rightarrow h=\dfrac{P_a}{\rho g}\\\Rightarrow h=\dfrac{101325}{1000\times 9.81}\\\Rightarrow h=10.32874\ m$

The maximum height to which Superman can lift the water is 10.32874 m

On the Moon there is no atmosphere so no atmospheric pressure which means when the straw is placed in water water will not rise in the tube.

5 0

3 years ago