All categories

3 years ago

2) Two railway tracks are parallel to west east direction. Along one track, train A moves with a speed of 45 m/s from

Physics

1 answer:

OLEGan [10]3 years ago

4 0

Answer:

$Relative\ Velocity = 105m/s$

Explanation:

Given

$V_A = 45m/s$

$V_B = 60m/s$

Required

Determine the speed of B w.r.t A

The question implies that, we determine the relative velocity of B w.r.t A

Because both trains are moving towards one another, the required velocity is a $sum\ of\ velocities\ of$ both trains:

This is shown below:

$Relative\ Velocity = V_A + V_B$

$Relative\ Velocity = 45m/s + 60m/s$

$Relative\ Velocity = 105m/s$

You might be interested in

How are speed and velocity different?

liubo4ka [24]

Velocity tells you how fast and in what direction. Speed only tells how fast.

4 0

3 years ago

Read 2 more answers

Part b suppose the magnitude of the gravitational force between two spherical objects is 2000 n when they are 100 km apart. what

kobusy [5.1K]

<span>b) The force with a distance of 150 km is 889 N c) The force with a distance of 50 km is 8000 N This question looks like a mixture of a question and a critique of a previous answer. I'll attempt to address the original question. Since the radius of the spherical objects isn't mentioned anywhere, I will assume that the distance from the center of each spherical object is what's being given. The gravitational force between two masses is given as F = (G M1 M2)/r^2 where F = Force G = gravitational constant M1 = Mass 1 M2 = Mass 2 r = distance between center of masses for the two masses. So with a r value of 100 km, we have a force of 2000 Newtons. If we change the distance to 150 km, that increases the distance by a factor of 1.5 and since the force varies with the inverse square, we get the original force divided by 2.25. And 2000 / 2.25 = 888.88888.... when rounded to 3 digits gives us 889. Looking at what looks like an answer of 890 in the question is explainable as someone rounding incorrectly to 2 significant digits. If the distance is changed to 50 km from the original 100 km, then you have half the distance (50/100 = 0.5) and the squaring will give you a new divisor of 0.25, and 2000 / 0.25 = 8000. So the force increases to 8000 Newtons.</span>

8 0

3 years ago

Read 2 more answers

A negative charge is moved from point A to point B along an equipotential surface. Which of the following statements must be tru

elena-s [515]

Answer:

C) No work is required to move the negative charge from point A to point B.

Explanation:

An equipotential surface is defined as a surface connecting all the points at the same potential.

Therefore, when a charge moves along an equipotential surface, it moves between points at same potential.

The work done when moving a charge is given by

$W=q\Delta V$

where

q is the charge

$\Delta V$ is the potential difference between the initial and final point of motion of the charge

However, the charge in this problem moves along an equipotential surface: this means that the potential does not change, so

$\Delta V=0$

And so, the work done is also zero.

7 0

4 years ago

A simple pendulum is used to determine the acceleration due to gravity at the surface of a planet. The pendulum has a length of

SVEN [57.7K]

Answer:

Acceleration due to gravity is 20 $m/sec^2$

So option (E) will be correct answer

Explanation:

We have given length of the pendulum l = 2 m

Time period of the pendulum T = 2 sec

We have to find acceleration due to gravity g

We know that time period of pendulum is given by

$T=2\pi \sqrt{\frac{l}{g}}$

$2=2\times 3.14 \sqrt{\frac{2}{g}}$

$0.3184= \sqrt{\frac{2}{g}}$

Squaring both side

$0.1014= {\frac{2}{g}}$

$g=19.71=20m/sec^2$

So acceleration due to gravity is 20 $m/sec^2$

So option (E) will be correct answer.

8 0

3 years ago

Inside a 30.2 cm internal diameter stainless steel pan on a gas stove water is being boiled at 1 atm pressure. If the water leve

dybincka [34]

Answer:

Q = 20.22 x 10³ W = 20.22 KW

Explanation:

First we need to find the volume of water dropped.

Volume = V = πr²h

where,

r = radius of pan = 30.2 cm/2 = 15.1 cm = 0.151 m

h = height drop = 1.45 cm = 0.0145 m

Therefore,

V = π(0.151 m)²(0.0145 m)

V = 1.038 x 10⁻³ m³

Now, we find the mass of the water that is vaporized.

m = ρV

where,

m = mass = ?

ρ = density of water = 1000 kg/m³

Therefore,

m = (1000 kg/m³)(1.038 x 10⁻³ m³)

m = 1.038 kg

Now, we calculate the heat required to vaporize this amount of water.

q = mH

where,

H = Heat of vaporization of water = 22.6 x 10⁵ J/kg

Therefore,

q = (1.038 kg)(22.6 x 10⁵ J/kg)

q = 23.46 x 10⁵ J

Now, for the rate of heat transfer:

Rate of Heat Transfer = Q = q/t

where,

t = time = (18.6 min)(60 s/1 min) = 1116 s

Therefore,

Q = (23.46 x 10⁵ J)/1116 s

8 0

3 years ago