answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Delicious77 [7]
2 years ago
10

A train travels a distance of 1,2 km between two stations with an average velocity of 43.2 km/h. During it's motion, at the time

t1=40s it moved accelerated, then at time t2 it moved uniformly, then at t3=40s it moved uniformly slowed. Find the maximum velocity of the train. The acceleration during the slowed motion is equal in modulus to the acceleration during the accelerated motion.
Physics
1 answer:
notsponge [240]2 years ago
7 0
For the answer to the question above,
The whole trip covered d = 1.2 km at 43.2 km/hr taking a total time of T = (1.2 / 43.2) hr = 100 s. Since T = t1 + t2 + t3 and t1=t3=40 s, then t2 = 100-40-40 = 20 s. 

<span>The area under the v vs. t curve is the distance d traveled. The shape of the curve is an isosceles trapezoid (trapezium in UK English) with bases T and t2 and height V. So, from the area formula for a trapezoid: </span>

<span>d = (V/2)(T + t2) </span>
<span>V = 2D / (T + t2) = (2.4 km) / (120 s) = 0.02 km/s </span>

<span>Multiply by 3600 s/hr to get 72 km/h to match the original units in the problem</span>
You might be interested in
Car A rounds a curve of 150‐m radius at a constant speed of 54 km/h. At the instant represented, car B is moving at 81 km/h but
Snezhnost [94]

Answer:

Velocity of Afrom B=21m/s

Acceleration of A from B=1.68m/s°2

Explanation:

Given

Radius r=150m

Velocity of a Va= 54km/hr

Va=54*1000/3600=15m/s

Velocity of b Vb=82km/hr

VB=81*1000/3600=22.5mls

The velocity of Car A as observed from B is VBA

VB= VA+VBA

Resolving the vector into X and Y components

For X component= 15cos60=7.5m/s

Y component=22 5sin60=19.48m/s

VBA= √(X^2+Y^2)

VBA= ✓(7.5^2+19.48^2)=21m/s

For acceleration of A observed from B

A=VA^2/r= 15^2/150=1.5m/s

Resolving into Xcomponent=1.5cos60=0.75m/s

Y component=3cos60=1.5

Acceleration BA=√(0.75^2+1.5^2)

1.68m/s

4 0
2 years ago
Read 2 more answers
An overhead projector lens is 32.0 cm from a slide (the object) and has a focal length of 30.1 cm. What is the magnification of
puteri [66]

Answer: 15.8

Explanation:

You are given that the

Object distance U = 32 cm

Focal length F = 30.1 cm

First calculate the image distance V by using the formula

1/F = 1/U + 1/V

Substitute F and V into the formula

1/30.1 = 1/32 + 1/V

1/V = 1/30.1 - 1/32

1/V = 0.00197259

Reciprocate both sides

V = 506.94 cm

Magnification M is the ratio of image distance to object distance.

M = V/U

substitute the values of V and U into the formula

M = 506.94/32

M = 15.8

Therefore, the magnification of the image is 15.8 or approximately 16.

6 0
2 years ago
A solid, uniform disk of mass M and radius a may be rotated about an axis parallel to the disk axis, at variable distances from
cricket20 [7]

Answer:

the function varies linearly with the radius of the disk, so the smallest period is zero for a radius of zero centimeters

Explanation:

This system performs a simple harmonic movement where the angular velocity is given by

         w = √ k / I

Where k is the constant recovered from the axis of rotation and I is the moment of inertia of the disk

The expression for the moment of inertia is

           I = 1/2 m r²

Angular velocity, frequency and period are related

         w = 2π f = 2π / T

Substituting

             2π / T = √ k / I

             T = 2π √ I / k

             T = 2π √ (½ m r² / k)

             T = (2π √m / 2k)   r

 

We can see that the function varies linearly with the radius of the disk, so the smallest period is zero for a radius of zero centimeters

6 0
2 years ago
For a magnetic field strength of 2T, estimate the magnitude of the maximum force on a 1-mm-long segment of a single cylindrical
nydimaria [60]

Answer:

Incomplete question

This is the complete question

For a magnetic field strength of 2 T, estimate the magnitude of the maximum force on a 1-mm-long segment of a single cylindrical nerve that has a diameter of 1.5 mm. Assume that the entire nerve carries a current due to an applied voltage of 100 mV (that of a typical action potential). The resistivity of the nerve is 0.6ohms meter

Explanation:

Given the magnetic field

B=2T

Lenght of rod is 1mm

L=1/1000=0.001m

Diameter of rod=1.5mm

d=1.5/1000=0.0015m

Radius is given as

r=d/2=0.0015/2

r=0.00075m

Area of the circle is πr²

A=π×0.00075²

A=1.77×10^-6m²

Given that the voltage applied is 100mV

V=0.1V

Given that resistive is 0.6 Ωm

We can calculate the resistance of the cylinder by using

R= ρl/A

R=0.6×0.001/1.77×10^-6

R=339.4Ω

Then the current can be calculated, using ohms law

V=iR

i=V/R

i=0.1/339.4

i=2.95×10^-4 A

i=29.5 mA

The force in a magnetic field of a wire is given as

B=μoI/2πR

Where

μo is a constant and its value is

μo=4π×10^-7 Tm/A

Then,

B=4π×10^-7×2.95×10^-4/(2π×0.00075)

B=8.43×10^-8 T

Then, the force is given as

F=iLB

Since B=2T

F=iL(2B)

F=2.95×10^-4×2×8.34×10^-8

F=4.97×10^-11N

7 0
2 years ago
You throw a baseball (mass 0.145 kg) vertically upward. It leaves your hand moving at 12.0 m/s. Air resistance can be neglected.
Andru [333]

Answer:

The ball will have an upward velocity of 6 m/s at a height of 5.51 m.

Explanation:

Hi there!

The equations of height and velocity of the ball are the following:

y = y0 + v0 · t + 1/2 · g · t²

v = v0 + g · t

Where:

y = height at time t.

y0 = initial height.

v0 = initial velocity.

t = time.

g = acceleration due to gravity (-9.81 m/s² considering the upward direction as positive).

v = velocity of the ball at time t.

Placing the origin at the throwing point, y0 = 0.

Let´s use the equation of velocity to obtain the time at which the velocity is 12.0 m/s / 2 = 6.00 m/s.

v = v0 + g · t

6.00 m/s = 12.0 m/s -9.81 m/s² · t

(6.00 - 12.0)m/s / -9.81 m/s² = t

t = 0.612 s

Now, let´s calculate the height of the baseball at that time:

y = y0 + v0 · t + 1/2 · g · t²     (y0 = 0)

y = 12.0 m/s · 0.612 s - 1/2 · 9.81 m/s² · (0.612 s)²

y = 5.51 m

The ball will have an upward velocity of 6 m/s at a height of 5.51 m.

Have a nice day!

4 0
2 years ago
Other questions:
  • Assume that a cloud consists of tiny water droplets suspended (uniformly distributed,
    13·1 answer
  • A vector A is added to B=6i-8j. The resultant vector is in the positive x direction and has a magnitude equal to A . What is the
    12·2 answers
  • An object having a mass of 2.0 kilograms falls from a height of 15 meters. What is its kinetic energy when it hits the ground?
    13·1 answer
  • The Pickering nuclear power plant has a power rating of 3100 MW.
    11·1 answer
  • A straight wire in a magnetic field experiences a force of 0.030 N when the current in the wire is 2.7 A. The current in the wir
    8·1 answer
  • A 5⁢kg object is released from rest near the surface of a planet such that its gravitational field is considered to be constant.
    11·1 answer
  • A spring stretches 0.018 m when a 2.8-kg object is suspendedfrom its end. How much mass should be attached to this spring sothat
    9·1 answer
  • A record player turntable initially rotating at 3313 rev/min is braked to a stop at a constant rotational acceleration. The turn
    12·1 answer
  • Select the correct answer from the drop-down menu. A box contains shirts in two different colors and two different sizes. The nu
    14·2 answers
  • Peter left Town A at 13:30 and travelled towards Town B at an
    11·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!