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Advocard [28]
3 years ago
5

A sprinter accelerates from rest to a top speed of 24 km/h in 2 seconds and then runs at a constant velocity for the rest of the

100 meter dash,
a- what was the distance he covered in the first 2 seconds

b- what was his time for the whole race
Physics
1 answer:
Tems11 [23]3 years ago
5 0

Answer:

a. 6.67 meters

b. 16 seconds

Explanation:

a. v=(24×1000)/3600=6.67 m/s

v=u-at

a=(v-u)/t=(6.67-0)/2=3.335 m/s^2

s=ut+(1/2) at^2 = 0×2+.5×3.335×(2)²=6.67 meters

b. After 2seconds, he ran at a constant velocity. From a, in 2 seconds, he crossed 6.67 meters.

So, distance left =(100-6.67)=93.33 meters

to cross 93.33 meters,he needed,

s=vt

93.33=6.67t

t=13.99≡14 seconds

So, Total (93.33+6.67)=100 meters were covered in (14+2)=16 seconds

Hope, this helps you.

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Fluorescence occurs when an object absorbs ____________________ and immediately releases the energy as visible light.
soldier1979 [14.2K]

Answer:

The answer should be light or other electromagnetic radiation

Explanation:

Such as x-rays or other things like that.

<em>-Hope This Helps!</em>

<em>-Justin:)</em>

5 0
2 years ago
What is the difference between a graph of linear motion and a graph of harmonic motion?
fredd [130]
Hope this helps :)

When describing linear motion, you need only one graph representing each of the three terms, while projectile motion requires a graph of the x and y axes. Graphs of simple harmonic motion are sine curves. Circular motion is different from other forms of motion because the speed of the object is constant.
5 0
3 years ago
Suppose Earth's gravitational force were decreased by half. How would this change affect a game of basketball? Write a paragraph
timama [110]
If the gravitational force were<span> decreased by half, there would be lack of gravity on earth. Hence, it would basically affect the velocity, speed, and the distance travelled in any direction by basketball players and the ball. The basketball would bounce higher and come down in a slower speed. Whereas for the players, they would be able to leap higher from the floor.</span><span> </span>
7 0
3 years ago
An investigator collects a sample of a radioactive isotope with an activity of 490,000 Bq.48 hours later, the activity is 110,00
Daniel [21]

Answer:

The correct answer is "22.27 hours".

Explanation:

Given that:

Radioactive isotope activity,

= 490,000 Bq

Activity,

= 110,000 Bq

Time,

= 48 hours

As we know,

⇒ A = A_0 e^{- \lambda t}

or,

⇒ \frac{A}{A_0}=e^{-\lambda t}

By taking "ln", we get

⇒ ln \frac{A}{A_0}=- \lambda t

By substituting the values, we get

⇒ -ln \frac{110000}{490000} = -48 \lambda

⇒    -1.4939=-48 \lambda

                 \lambda = 0.031122

As,

⇒ \lambda = \frac{ln_2}{\frac{T}{2} }

then,

⇒ \frac{ln_2}{T_ \frac{1}{2} } =0.031122

⇒ T_\frac{1}{2}=\frac{ln_2}{0.031122}

         =22.27 \ hours  

3 0
3 years ago
A ball rolls from x=3.85m to x=22.1m in 5 seconds. What was its average velocity
Vadim26 [7]

Answer:

Average Velocity = 3.65 m/s

Explanation:

Average Velocity  =\frac{Total   Displacement}{Total     Time} =\frac{22.1-3.85}{5}=\frac{18.25}{5}=3.65

3 0
2 years ago
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