1answer.
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
Diano4ka-milaya [45]
3 years ago
8

A train at a constant 79.0 km/h moves east for 27.0 min, then in a direction 50.0° east of due north for 29.0 min, and then west

for 37.0 min. What are the (a) magnitude and (b) angle (relative to east) of its average velocity during this trip?
Physics
1 answer:
ivolga24 [154]3 years ago
6 0

Answer:

Magnitude of avg velocity, |v_{avg}| = 18.9 km/h

\theta' = 56.85^{\circ}

Given:

Constant speed of train, v = 79 km/h

Time taken in East direction, t = 27 min = \frac{27}{60} h

Angle, \theta = 50^{\circ}

Time taken in 50^{\circ}east of due North direction, t' = 29 min =  \frac{29}{60} h

Time taken in west direction, t'' = 37 min =  \frac{27}{60} h

Solution:

Now, the displacement, 's' in east direction is given by:

\vec{s} = vt = 79\times \frac{27}{60} = 35.5\hat{i} km

Displacement in  50^{\circ} east of due North for 29.0 min is given by:

\vec{s'} = vt'sin50^{\circ}\hat{i} + vt'cos50^{\circ}\hat{j}

\vec{s'} = 79(\frac{29}{60})sin50^{\circ}\hat{i} + 79(\frac{29}{60})cos50^{\circ}\hat{j}

\vec{s'} = 29.25\hat{i} + 24.54\hat{j} km

Now, displacement in the west direction for 37 min:

\vec{s''} = - vt''hat{i} = - 79\frac{37}{60} = - 48.72\hat{i} km

Now, the overall displacement,

\vec{s_{net}} = \vec{s} + \vec{s'} + \vec{s''}

\vec{s_{net}} = 35.5\hat{i} + 29.25\hat{i} + 24.54\hat{j} - 48.72\hat{i}

\vec{s_{net}} =  16.03\hat{i} + 24.54\hat{j} km

(a) Now, average velocity, v_{avg} is given:

v_{avg} = \frac{total displacement, \vec{s_{net}}}{total time, t}

v_{avg} = \frac{16.03\hat{i} + 24.54\hat{j}}{\frac{27 + 29 + 37}{60}}

v_{avg} = 10.34\hat{i} + 15.83\hat{j}) km/h

Magnitude of avg velocity is given by:

|v_{avg}| = \sqrt{(10.34)^{2} + (15.83)^{2}} = 18.9 km/h

(b) angle can be calculated as:

tan\theta' = \frac{15.83}{10.34}

\theta' = tan^{- 1}\frac{15.83}{10.34} = 56.85^{\circ}

You might be interested in
Describe the sequence of mechanical energy events that lets you hear the
lina2011 [118]

Answer:

Starting from the beginning.

There is a radio signal that is received by the radio.

The radio interprets the signal and produces a current in response to it.

That current goes to a membrane that oscillates producing sound, the oscillation of the membrane is the first mechanical energy event here.

These oscillations can travel in material mediums, for example, the air. Then there is a production of waves (soundwaves) that travel in the air (second event).

Those waves now hit the wall that separates you and your neighbor, as the wall is made of a material, the soundwaves can travel through it, but they will be dispersed (a part of the waves rebounds on the wall, and another part is dissipated as the wave travels through the wall), there is also a transmitted part of the wave, that is now in your house. (this change of medium will be the third event). Now only the lower frequencies survive, this is why the sound is "muffled".

Those remaining frequencies now travel in your house, and when they reach your ear, your ear sends a signal to your brain and your brain interprets them as sound. The wave interacting with your ear will be the fourth and last mechanical energy event.

3 0
2 years ago
The blades in a blender rotate at a rate of 6800 rpm . When the motor is turned off during operation, the blades slow to rest in
tangare [24]
The angular acceleration of the blade when it's switched off is (-6800 rev/min) divided by (2.8 sec) = -2,428.6 rev/(min-sec) = -40.5 rev/sec^2 .
5 0
3 years ago
A 0.50-kg mass attached to the end of a string swings in a vertical circle (radius 2.0 m). When the mass is at the highest point
il63 [147K]

Answer:

31.1 N

Explanation:

m = mass attached to string = 0.50 kg

r = radius of the vertical circle = 2.0 m

v = speed of the mass at the highest point = 12 m/s

T = force of the string on the mass attached.

At the highest point, force equation is given as

T + mg =\frac{mv^{2}}{r}

Inserting the values

T + (0.50)(9.8) =\frac{(0.50)(12)^{2}}{2}

T = 31.1 N

7 0
3 years ago
Read 2 more answers
How can you prove to other people that your theory should become a law?
elena-s [515]
By giving them an advice and by giving them encouraging and explaining the any theory
3 0
2 years ago
What is angular velocity
butalik [34]

Answer:

angular velocity(ω) is the rate change of angular displacement.

ω=θ/t and it SI unit is rad/s

Explanation:

this is very similar with the definition of linear velocity (rate of change of displacement). it specifies the angular speed of an object and the axis about which the object is rotating.

7 0
2 years ago
Other questions:
  • a car traveling at 28 m/s slows down at a constant rate for 4 seconds until it stops. what is its acceleration?
    13·1 answer
  • A free body diagram of a brick on an inclined plane is shown below. What is the mechanical advantage of the inclined plane?
    9·1 answer
  • Addition of a metal slab of thickness "a" between the plates of a parallel plate capacitor of plate separation "d" is equivalent
    12·1 answer
  • A pendulum is made of a small sphere of mass 0.250 kg attached to a lightweight string 1.20 m in length. As the pendulum swings
    14·1 answer
  • What voltage would be measured across the 15 ohm resistor?
    11·2 answers
  • The most common patterns of minority treatment include assimilation, segregation, subjugation, and legal protection.
    6·2 answers
  • An owl is carrying a vole in its talons, flying in a horizontal direction at 8.3 m/s while 282 m above the ground. The vole wigg
    14·1 answer
  • A 0.75 kilogram apple is thrown upward from the ground. The apple reaches a height of 5.5m, what is the beginning gravitational
    15·1 answer
  • Cutting down the forest reduces the size of animal habitats, increases erosion, and results in an increase in the amount of carb
    7·1 answer
  • What's is the origin of Neptune's moon Triton?​
    6·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!