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2 years ago

Near the end of a marathon race, the first two runners are separated by a distance of

Physics

1 answer:

yuradex [85]2 years ago

6 0

Answer:

a) 4.75-3.25 = 1.50 m/s

b) Time taken to overtake = 65/1.5 = 43.33 seconds

first runner will finish the race in 215/3.25 = 66.15 seconds

So second runner will win the race

ANSWER

c) 65 +215 = 280m

280 / 4.75 = 58.95 seconds

first runner will complete 58.95 X 3.25 = 191.5875 m

So 215-191.5875=23.4125 meters ahead

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Man made objects that spread an impulse over a large amount of time

lyudmila [28]

Answer:

Examples of man-made objects that spread an impulse over a large amount of time are "airbags" in vehicles and "arrestor beds" (for trucks).

Explanation:

The question above is highly related to the topic about "Impulse" in Physics.

"Impulse" refers to an object's change in momentum (the amount of motion in an object) when a force acts upon it for an interval time. When it comes to providing safety to people when it comes to vehicular crashes, impulse plays a vital role.

Let's take the example of airbags in vehicles. Once a vehicle collides with another object, the driver is carried by a forward motion. Without airbags, the time is normally shorter for the driver to be stopped by the windshield. This results to a greater force. However, with the presence of air-bags, the driver will hit the airbag, instead of the windshield. This will lengthen the time of the impact, thus reducing the force.

Another example are the arrestor beds for trucks. Arrestor beds have been designed in order for trucks to stop, since it's hard to maneuver them. With the help of arrestor beds, trucks are able to come to a stop with a longer time interval, but decreased force.

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2 years ago

Anyone.... help with this two questions...

PSYCHO15rus [73]

Answer:

what is the question

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Explanation:

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2 years ago

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Select all that apply. The force that opposes the start of motion is referred to as _____.

77julia77 [94]

The correct answers are starting friction and static friction

Friction slows down all forces, but starting friction slows down or stops completely the start of motion.

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2 years ago

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A dolphin in an aquatic show jumps straight up out of the water at a velocity of 13.0 m/s.

SVEN [57.7K]

Answer:

a) Knowns, initial speed $v_{i}=13.0 m/s$ , final speed $v_{f}=0 m/s$ and gravity due it is a constant $g=9.8m/s^{2}$

b) The maximum high reached by the dolphin is $y_{max}=8.62 m$

c) Total time is $t=2.65s$

Explanation:

a) First of all the initial speed is given at the start of the problem, gravity is constant and final speed is known any object thrown straight up reaches its max high at $0m/s$ speed.

b) Second, now that we know final speed we use $v_{f} =v_{i}-gt$ , as we clear for $t=\frac{v_{i}-v_{f} }{g}=\frac{20.0m/s}{9.8m/s^{2} }=1.32 s$ .

Then we use $y=v_{i}t-\frac{1}{2} gt^{2}=(20.0m/s)(1.32s)-\frac{1}{2} (9.8m/s^{2} ) (1.32s)^{2} =8.62m$

c)Third, finally we can use $y=v_{i}t-\frac{1}{2} gt^{2}$ , as we know $y=0m$ when the dolphin fall into the water again and $v_{i} =13.0m/s$ , then we have $0=(13m/s)t-\frac{1}{2} (9.8m/s^{2} )t^{2}$ is a quadratic form $0=t(13.0-4.9t)$ so we have $t_{i}=0s$ and $t_{f}=\frac{13}{4.90} =2.65s$

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2 years ago

The earth rotates every 86,160 seconds. What is the tangential speed (in m/s) at Livermore (Latitude 37.6819° measured up from e

Lena [83]

Answer:

The tangential speed at Livermore is approximately 284.001 meters per second.

Explanation:

Let suppose that the Earth rotates at constant speed, the tangential speed ( $v$ ), measured in meters per second, at Livermore (37.6819º N, 121º W) is determined by the following expression: