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oee [108]
3 years ago
14

A 1100 kg automobile is at rest at a traffic signal. At the instant the light turns green, the automobile starts to move with a

constant acceleration of 5.0 m/s2. At the same instant a 2000 kg truck, traveling at a constant speed of 7.0 m/s, overtakes and passes the automobile. A)How far is the com of the automobile-truck system from the traffic light at t=3.0 s? B)What is the speed of the com then?
Physics
1 answer:
Viktor [21]3 years ago
6 0

Answer:

a ) 21 m b) 7 m/s

Explanation:

For this case, we can consider for our reference system, that point zero (this is, at the rest of the traffic signal) is when X₀ = 0, and direction of movement is from left to right (positive sign)

For the car:  

a= acceleration is constant = 5 m/s² m1 , mass = 1100 Kg , V = not constant

This is an uniformly accelerated rectilinear movement, and applicable formulas are:

V = V₀ + at , X = X₀ + V₀t + 1/2at²

For the truck:

V = speed is constant = 7 m/s , mass = 2000 Kg, a = 0

This is an uniform rectilinear movement, and the applicable formula is:

X = X₀ + Vt

a) At t = 3.0 sec, we can use the formula for the track, considering that X₀ = 0 (when it pass the rest of the traffic signal)

X = 0 + (7 m/s)x(3 s) = 21 m  

So, at 3 sec, truck will be at 21 m from the rest of traffic light and, as truck has a constant speed; at that exact second; truck and car will be together as a com, so both will be 21 m away from point zero

b) At the exact time (3 sec, or in distance words, 21 m) car and truck will be together as a com, so they will both have the exact speed, hence, speed of car at that point will be 7 m/s

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Answer:

B. The maximum angle decreases

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So the tan of angle of repose θ is proportional to coefficient of static friction.

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7 0
3 years ago
A student examines a 20-meter long rectangular stream channel and takes the following measurements: width of stream = 4 meters,
Scrat [10]

Answer:

The discharge of the stream at this location is 40 cubic meters per second.

Explanation:

The discharge is the volume flow rate of the water in the stream. For this purpose we can use the following formula:

Discharge = Volume Flow Rate = (Cross-Sectional Area)(Velocity of Stream)

Volume Flow Rate = (Width of Stream)(Depth of Stream)(Velocity of Stream)

Volume Flow Rate = (4 meters)(2 meters)(5 meters per second)

<u>Volume Flow Rate = 40 cubic meters per second</u>

Therefore, the discharge of the stream at this location is found to be <u>40 cubic meters per second</u>

This result shows that 40 cubic meters volume of water passes or discharges through this point in a time of one second. Hence, this is called the volume flow rate or the discharge of the stream.

3 0
3 years ago
If a ball is tossed straight up into the air, at what position is its potential energy the greatest? Question 2 options: a) when
yarga [219]
Q1: At the highest point
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3 years ago
A car owner forgets to turn off the headlights of his car while it is parked in his garage. If the 12.0-V battery in his car is
avanturin [10]

Answer: 22.6 hours

Explanation:

The power is the measure of the rate of energy.

In this problem, the 12.0 V battery is rated at 51.0 Ah, which means it delivers 51.0 A of current in a time of t = 1 h = 3600 s. The power delivered by the battery can be written as

P=IV

where

I is the current

V = 12.0 V is the voltage of the battery

So the energy delivered by the battery can be written as

E=Pt=VIt

Where

It=51.0 A\cdot h = 51.0 A \cdot 3600 s/h=183,600 A\cdot s

So the energy delivered is

E=(12.0)(183,600)=2.2\cdot 10^6 J

At the same time, the headlight consumes 27.0 W of power, so 27 Joules of energy per second; Therefore, it will remain on for a time of:

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3 0
3 years ago
A ball rolls for 8 seconds and travels 24 meters. How fast was it traveling?
belka [17]

Answer:

The speed of the ball was, v = 3 m/s

Explanation:

Given data,

The time period of the ball, t = 8 s

The distance the ball rolled, d = 24 m

The velocity of an object is defined as the object's displacement to the time taken. The formula for the velocity is,

                              v = d / t      m/s

Substituting the given values in the above equation,

                               v = 24 / 8

                                  = 3 m/s

Hence, the speed of the ball was, v = 3 m/s

8 0
3 years ago
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