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3 years ago

1. Why didn't Sucheng Chan go to school until she was eight

Physics

1 answer:

Crazy boy [7]3 years ago

3 0

Answer:

Because china was in war, and her parents didn't have enough money for to go to school.

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A light-rail train going from one station to the next on a straight section of track accelerates from rest at 1.1m/s^2 for 20s.

SSSSS [86.1K]

Answer:

A.) 1430 metres

B.) 80 seconds

Explanation:

Given that the train accelerates from rest at 1.1m/s^2 for 20s. The initial velocity U will be:

U = acceleration × time

U = 1.1 × 20 = 22 m/s

It then proceeds at constant speed for 1100 m

Then, time t will be

Time = distance/ velocity

Time = 1100/22

Time = 50 s

before slowing down at 2.2m/s^2 until it stops at the station.

Deceleration = velocity/time

2.2 = 22/t

t = 22/2.2

t = 10s

Using area under the graph, the distance between the two stations will be :

(1/2 × 22 × 20) + 1100 + (1/2 × 22 × 10)

220 + 1100 + 110

1430 m

The time taken between the two stations will be

20 + 50 + 10 = 80 seconds

6 0

3 years ago

Give an example of a collision in real life. Use the law of conservation of energy to describe the transfer of momentum. Be sure

ozzi

Explanation :

Using the law of conservation of energy

When two cars collide with each other then the momentum is same before collision and after collision but energy is changed after collision in form of heat and sound.

We know this collision is inelastic collision.

In Inelastic collision, when two objects collide with each other then the momentum is conserved but kinetic energy is not conserved.

7 0

3 years ago

A 12 V battery applies a potential difference to three resistors in series. If the potential at point P is 0.0 V, the potential

galina1969 [7]

This question is incomplete, the complete question is on the image uploaded along this answer.

Answer:

the potential at point B is 5 V, Option d) is the correct answer

Explanation:

Given that;

from the image;

R = 3 + 4 + 5 = 12 Ω

so I = 12/12 = 1 A

Q = 0 + 12 = 12 V

now

VA - VQ = - I × 3 = -3 V

VA = VQ - 3 = 12 - 3 = 9 V

VB - VA = - I × 4Ω = - 4 V

⇒VB = VA - 4 = 9 V - 4 V = 5 V

Therefore the potential at point B is 5 V

Option d) is the correct answer

4 0

3 years ago

Determine the mechanical advantage of a car jack that uses an input force of 30 N and provides an output force of 600 N. pls ans

Maslowich

Answer:

Mechanical Advantage of car jack is 20

4 0

3 years ago

Determine the frequency of the 2nd harmonic of a spring that has a 3rd harmonic resonance of f3=512 Hz.

Elena L [17]

Answer:

1) 341 Hz

Explanation:

When a string vibrates, it can vibrate with different frequencies, corresponding to different modes of oscillations.

The fundamental frequency is the lowest possible frequency at which the string can vibrate: this occurs when the string oscillate in one segment only.

If the string oscillates in n segments, we say that it is the n-th mode of vibration, or n-th harmonic.

The frequency of the n-th harmonic is given by

$f_n = nf_1$