Ask question

Ask question

All categories

VashaNatasha [74]

2 years ago

7

A train travels 190km in 3.0 hours and then 120 km in 2.0 hours. What is it’s average speed ?

1 answer:

xxMikexx [17]2 years ago

6 0

Answer:

60 km/h

Explanation:

Simplify the speed:

120÷2=60

Hence, the average speed is 60 km/h.

You might be interested in

A bowling ball is on the end of a rope of length 5 meters, the other end of which is attached to a hook in the ceiling. The ball

pogonyaev

Answer:

$a = 0\,\frac{m}{s^{2}}$

Explanation:

Let consider the following system, which is described in the image attached below and two reference axis, one parallel and the other perpendicular to the direction of motion. The corresponding equations of equilibrium are described herein:

$\Sigma F_{n} = T - m\cdot g \cdot \cos \theta = 0$

$\Sigma F_{t} = m\cdot g \cdot \sin \theta = m\cdot a$

The acceleration of the bowling ball at the lowest point occurs at $\theta = 0^{\textdegree}$

$m\cdot g \cdot \sin \theta = m\cdot a$

$g\cdot \sin \theta = a$

$a = 0\,\frac{m}{s^{2}}$

6 0

3 years ago

Two disks are mounted (like a merry-go-round) on low-friction bearings on the same axle and can be brought together so that they

nadezda [96]

Since no external torque is acting on the system you can use the conservation of angular momentum. I derived the final angular speed below and shown my work on how I did it. It’s now just a matter of plugging in the numbers and using correct placement of negative sign for direction of angular velocity. L in the picture stands for angular momentum. Hope it helps

4 0

3 years ago

The dome of a Van de Graaff generator receives a charge of 0.00011 C. The radius of the dome is 5.2 m. Find the strength of the

wel

Answer:

Answer:

Explanation:

Given that

K=8.98755×10^9Nm²/C²

Q=0.00011C

Radius of the sphere = 5.2m

g=9.8m/s²

1. The electric field inside a conductor is zero

εΦ=qenc

εEA=qenc

net charge qenc is the algebraic sum of all the enclosed positive and negative charges, and it can be positive, negative, or zero

This surface encloses no charge, and thus qenc=0. Gauss’ law.

Since it is inside the conductor

E=0N/C

2. Since the entire charge us inside the surface, then the electric field at a distance r (5.2m) away form the surface is given as

F=kq1/r²

F=kQ/r²

F=8.98755E9×0.00011/5.2²

F=36561.78N/C

The electric field at the surface of the conductor is 36561N/C

Since the charge is positive the it is outward field

3. Given that a test charge is at 12.6m away,

Then Electric field is given as,

E=kQ/r²

E=8.98755E9 ×0.00011/12.6²

E=6227.34N/C

5 0

2 years ago

A bystander observes the musicians heading toward each other. When musician #1 is 100 m away, the intensity is 1.24 x 10-8 W/m^2

777dan777 [17]

Explanation:

Given that,

Distance 1, r = 100 m

Intensity, $I_1=1.24\times 10^{-8}\ W/m^2$

If distance 2, r' = 25 m

We need to find the intensity and the intensity level at 25 meters. Intensity and a distance r is given by :

$I=\dfrac{P}{4\pi r^2}$ .........(1)

Let I' is the intensity at r'. So,

$I'=\dfrac{P}{4\pi r'^2}$ ............(2)

From equation (1) and (2) :

$I'=\dfrac{Ir}{r'^2}$

$I'=\dfrac{1.24\times 10^{-8}\times 100}{25^2}$

$I'=1.98\times 10^{-9}\ W/m^2$

Intensity level is given by :

$dB=10\ log(\dfrac{I'}{I_o})$ , $I_o=10^{-12}\ W/m^2$

$dB=10\ log(\dfrac{1.98\times 10^{-9}}{10^{-12}})$

dB = 32.96 dB

Hence, this is the required solution.

7 0

2 years ago

The greater the mass is in an object, the higher resistance to a change in movement the object will have.

Bond [772]

True. Since Inertia states this law, we are bound to believe greater mass = greater resistance in change of motion

3 0

2 years ago

Read 2 more answers