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
Alekssandra [29.7K]
3 years ago
6

If the sprinter from the previous problem accelerates at that rate for 20 m, and then maintains that velocity for the remainder

of the 100-m dash, what will be his time for the race?
Physics
1 answer:
kakasveta [241]3 years ago
5 0

Question:

A 63.0 kg sprinter starts a race with an acceleration of 4.20m/s square. What is the net external force on him? If the sprinter from the previous problem accelerates at that rate for 20m, and then maintains that velocity for the remainder for the 100-m dash, what will be his time for the race?

Answer:

Time for the race will be t = 9.26 s

Explanation:

Given data:

As the sprinter starts the race so initial velocity = v₁ = 0

Distance = s₁ = 20 m

Acceleration = a = 4.20 ms⁻²

Distance = s₂ = 100 m

We first need to find the final velocity (v₂) of sprinter at the end of the first 20 meters.

Using 3rd equation of motion

(v₂)² - (v₁)² = 2as₁ = 2(4.2)(20)

v₂ = 12.96 ms⁻¹

Time for 20 m distance = t₁ = (v₂ - v ₁)/a

t₁ = 12.96/4.2 = 3.09 s

He ran the rest of the race at this velocity (12.96 m/s). Since has had already covered 20 meters, he has to cover 80 meters more to complete the 100 meter dash. So the time required to cover the 80 meters will be

Time for 100 m distance = t₂ = s₂/v₂

t₂ = 80/12.96 = 6.17 s

Total time = T = t₁ + t₂ = 3.09 + 6.17 = 9.26 s

T = 9.26 s

You might be interested in
An alkane has molecular weight 86. Write its molecular formula. What will be its physical state?
Brums [2.3K]

C6H14

Gaseous state

it's unsaturated hence gaseous

8 0
3 years ago
An astronaut on an alien planet drops a rock into a crater which is 100 meters deep. The rock hits the bottom of the crater 4 se
Semmy [17]

Answer:

The gravity on this planet is stronger than that of earth.

Explanation:

First we need to find the acceleration due to gravity value of this planet to compare its gravity force with that of the earth. Hence, we will use second equation of motion:

h = Vi t + (0.5)gt²

where,

h = height or depth of crater = 100 m

Vi = Initial Velocity of rock = 0 m/s

t = time = 4 s

g = acceleration due to gravity on this planet = ?

Therefore,

100 m = (0 m/s)(4 s) + (0.5)(g)(4 s)²

g = (200 m)/(16 s²)

g = 12.5 m/s²

on earth:

ge = 9.8 m/s²

Since,

ge < g

Therefore,

<u>The gravity on this planet is stronger than that of earth.</u>

6 0
3 years ago
Explain three ways visual aids help you study
Katen [24]
Visual aids are tools that help to make an issue or lesson clearer or easier to understand and know (pictures, models, charts, maps, videos, slides, real objects etc.). ... Visual aids are those devices which are used in classrooms to encourage students learning process and make it easier and interesting.
7 0
2 years ago
A car travels west for 240 km in 4 h. what is the car's velocity?
nalin [4]
The velocity is 60 because you divide your distance by your time (240÷4=60)
4 0
3 years ago
Read 2 more answers
Mirage is due to...
Irina18 [472]
<span>Mirage is due to (A). unequal heating of different parts of the atmosphere,
because that produces unequal density of different parts of the atmosphere,
which bends the light.
</span>
3 0
3 years ago
Other questions:
  • Kilogram is a unit of volume.<br> a. True<br> b. False
    14·1 answer
  • Can someone explain what ice jacking is and how it can cause structures to fail?
    7·1 answer
  • During an autopsy and subsequent toxicology reports, it is discovered that a man died from arsenic poisoning. When investigating
    10·1 answer
  • Object A has mass mA = 9 kg and initial momentum vector pA,i = &lt; 20, -6, 0 &gt; kg · m/s, just before it strikes object B, wh
    13·1 answer
  • Do comets have a liquid center
    13·1 answer
  • The angular velocity of a 755-g wheel 15.0 cm in diameter is given by the equation ω(t) = (2.00 rad/s2)t + (1.00 rad/s4)t 3. (a)
    7·1 answer
  • Describe how Bohr’s model used the work of Maxwell.
    15·1 answer
  • A driver is traveling along a straight road at the speed limit of 60 mph. After two minutes, she slows at a constant rate to a s
    13·1 answer
  • 2.1kilograms into grams (1000g=1kg)
    14·1 answer
  • It is cold and dry outside. You go down the slide and experience a small electric shock. What charge must you and slide be in or
    11·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!