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
Natasha2012 [34]
3 years ago
5

A world-class sprinter running a 100 m dash was clocked at 5.4 m/s 1.0 s after starting running and at 9.8 m/s 1.5 s later. In w

hich of these time intervals, 0 to 1.0 s or 1.0 s to 2.5 s, was his output power greater?
Physics
1 answer:
cupoosta [38]3 years ago
6 0

Answer:

<em>The output power is greater in the interval from 1.0 s to 2.5 s</em>

Explanation:

<u>Physical Power </u>

It measures the amount of work W an object does in certain time t. The formula needed to compute power is

\displaystyle P=\frac{W}{t}

Work can be computed in several ways since we are given the motion conditions, we'll use this formula, for F= applied force, x=distance parallel to F

W=F.x

The second Newton's law gives us the net force as

F=m.a

being m the mass of the object and a the acceleration it has for a given period of time. In our problem, we have two different behaviors for each interval and we must calculate this force since the acceleration is changing. Let's calculate the acceleration in the first interval. We can use the formula for the final speed vf knowing the initial speed vo (which is 0 because the sprinter starts from rest), the acceleration a, and the time t:

v_f=v_o+at

v_f=at

Solving for a

\displaystyle a=\frac{v_f}{t}={5.4}{1}

a=5.4\ m/s^2

The distance traveled in the interval is given by

\displaystyle x=v_o.t+\frac{a.t^2}{2}

Since vo=0

\displaystyle x=\frac{a.t^2}{2}=\frac{5.4(1)^2}{2}

x=2.7\ m

The force is given by

F=m.a

We don't know the value of m, so the force is

F=2.7m

Computing the work done by the sprinter

W=F.x=2.7m(5.4)

W=14.58m

The power is finally computed

\displaystyle P=\frac{W}{t}=\frac{14.58m}{1}

P=14.58m

During the second interval, from t=1 sec to 1.5 sec, the speed changes from 5.4 m/s to 9.8 m/s. This allows us to compute the second acceleration

\displaystyle a=\frac{v_f-v_o}{t}=\frac{9.8-5.4}{0.5}

a=8.8\ m/s^2

The distance is

\displaystyle x=(5.4).(0.5)+\frac{8.8(0.5)^2}{2}

x=3.8\ m

The net force is

F=m(8.8)=8.8m

The work done by the sprinter is now computed as

W=8.8m(3.8)=33.44m

At last, the output power is

\displaystyle P=\frac{33.44m}{0.5}=66.88m

By comparing both results, and being m the same for both parts, we conclude the output power is greater in the interval from 1.0 s to 2.5 s

You might be interested in
20. For each improvement in glider design, engineers follow
AleksandrR [38]
B. Engineers perform lots of trials.
5 0
2 years ago
What is 7.4×10 to the second power​
sleet_krkn [62]
The correct answer is 740
8 0
3 years ago
A constant force of 2.5 N to the right acts on a 4.5 kg mass for 0.90 s.
Alborosie

Answer:

(a) v_f=0.5\frac{m}{s}

(b) v_f=-11\frac{m}{s}

Explanation:

(a) Since a constant external force is applied to the body, it is under an uniformly accelerated motion. Using the following kinematic equation, we calculate the final velocity of the mass  if it is initially at rest(v_0=0):

v_f=v_0+at\\v_f=at(1)

According to Newton's second law:

F=ma\\a=\frac{F}{m}(2)

Replacing (2) in (1):

v_f=\frac{F}{m}t\\v_f=\frac{2.5N}{4.5kg}(0.9s)\\v_f=0.5\frac{m}{s}

(b) In this case we have v_0=-11.5\frac{m}{s}. So, we use the final velocity equation:

v_f=v_0+at\\v_f=v_0+\frac{F}{m}t\\v_f=-11.5\frac{m}{s}+\frac{2.5N}{4.5kg}(0.9s)\\v_f=-11\frac{m}{s}

8 0
3 years ago
You are working as an assistant to an air-traffic controller at the local airport, from which small airplanes take off and land.
Alika [10]

Answer:

d = 2021.6 km

Explanation:

We can solve this distance exercise with vectors, the easiest method s to find the components of the position of each plane and then use the Pythagorean theorem to find distance between them

Airplane 1

Height   y₁ = 800m

Angle θ = 25°

           cos 25 = x / r

           sin 25 = z / r

           x₁ = r cos 20

           z₁ = r sin 25

          x₁ = 18 103 cos 25 = 16,314 103 m = 16314 m

          z₁ = 18 103 sin 25 = 7,607 103 m= 7607 m

2 plane

Height   y₂ = 1100 m

Angle θ = 20°

          x₂ = 20 103 cos 25 = 18.126 103 m = 18126 m

          z₂ = 20 103 without 25 = 8.452 103 m = 8452 m

The distance between the planes using the Pythagorean Theorem is

         d² = (x₂-x₁)² + (y₂-y₁)² + (z₂-z₁)²2

Let's calculate

        d² = (18126-16314)²  + (1100-800)² + (8452-7607)²

        d² = 3,283 106 +9 104 + 7,140 105

        d² = (328.3 + 9 + 71.40) 10⁴

        d = √(408.7 10⁴)

        d = 20,216 10² m

        d = 2021.6 km

7 0
3 years ago
Work is a transfer of (1 point) energy. force. mass. motion.
jok3333 [9.3K]
Energy is the ability to do work.

So work can not be done without the transfer of energy from one body to another.

Work is the transfer of energy.
6 0
3 years ago
Read 2 more answers
Other questions:
  • Which theory proposed by Galileo is considered a “big mistake of his life”? What did the theory state, and why was it a “big mis
    5·2 answers
  • Avogadro’s law and charles’s law describe a proportionality of the volume of a gas when the pressure is constant. Describe the p
    5·1 answer
  • Ali and Abdi go for a walk along an abandoned railroad truck , Ali puts one ear next to a rail, while Abdi 300m away taps in the
    5·1 answer
  • What kind of energy involves the flow of positive charges?
    9·2 answers
  • What is the acceleration of a car moving in a straight line at a constant velocity of 50 km/hr for 10 seconds?
    13·1 answer
  • 1. A body whose mass is 2 kg and has a volume of 500cm just floats
    12·1 answer
  • How do I eat Chinese caca
    14·2 answers
  • The curved speed time graph represents what acceleration motion​
    9·1 answer
  • A 2300-kg car slows down at a rate of 3.0 m/s2 when approaching a stop sign. What is the magnitude of the net force causing it t
    7·1 answer
  • How did Millikan's oil drop experiment lead to quantum nature of electric charge?​
    10·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!