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
givi [52]
3 years ago
8

Using energy considerations, calculate the average force a 60.0-kg sprinter exerts backward on the track to accelerate from 2.00

to 8.00 m/s in a distance of 25.0 m, if he encounters a headwind that exerts an average force of 30.0 N against him.
Physics
1 answer:
baherus [9]3 years ago
7 0

Answer:

F = 102 N

Explanation:

ASSUMING the track is horizontal to avoid gravity potential energy considerations.

The work of the applied force must overcome friction work and increase the kinetic energy of the runner

F(d) = Ff(d) + ½m(v² - u²)

F = Ff + m(v² - u²) / 2d

F = 30.0 + 60.0(8.00² - 2.00²) / (2(25.0))

F = 102 N

You might be interested in
A 600-g block is dropped onto a relaxed vertical spring that has a spring constant k =190.0 N/m. The block becomes attached to t
charle [14.2K]

Answer:

Work done will be 2.205 j

Explanation:

We have given that the spring is compressed b 37.5 cm

So d = 0.375 m

Mass of the block m = 600 gram = 0.6 kg

Acceleration due to gravity g=9.8m/sec^2

Gravitational force on the block F=mg=0.6\times 9.8=5.88N

Now we know that work done is give by W=Fd=5.88\times 0.375=2.205J

5 0
3 years ago
A girl rides her scooter to school, a total distance of 4.5km. She has to slow down twice to cross busy streets, but overall the
Whitepunk [10]

Answer:

6.93 km/h

Explanation:

To calculate her average speed, we need the "speed" formula, which is:

average speed = distance / time

You plug in your numbers and it will give you the answer.

Speed = 4.5km/0.65hr

           = 6.923 km/h

8 0
3 years ago
Read 2 more answers
A person with mass mp = 76 kg stands on a spinning platform disk with a radius of R = 1.98 m and mass md = 191 kg. The disk is i
nalin [4]
<span>1.7 rad/s The key thing here is conservation of angular momentum. The system as a whole will retain the same angular momentum. The initial velocity is 1.7 rad/s. As the person walks closer to the center of the spinning disk, the speed will increase. But I'm not going to bother calculating by how much. Just remember the speed will increase. And then as the person walks back out to the rim to the same distance that the person originally started, the speed will decrease. But during the entire walk, the total angular momentum remained constant. And since the initial mass distribution matches the final mass distribution, the final angular speed will match the initial angular speed.</span>
3 0
4 years ago
A train increases its speed steadily from 10 m/s to 20 m/s in
rewona [7]

Answer:

15m/s

Explanation:

add the two speeds and divide by 2

10+20=30

30/2=15

3 0
3 years ago
The amount of kinetic energy an object has depends upon which of the following factors? I. the object's velocity II. the object'
harina [27]

1.) The object's Velocity

Faster it goes, more kinetic energy it has

8 0
3 years ago
Other questions:
  • A sample of 4.50 g of methane occupies 12.7 dm3 at 310 K. (a) Calculate the work done when the gas expands isothermally against
    10·1 answer
  • Explain why the energy in the sun moves out toward the surface
    8·1 answer
  • At what distance will a 80 W lightbulb have the same apparent brightness as a 120 W bulb viewed from a distance of 40 m
    11·1 answer
  • A scientist conducting a field investigation records measurements of very low pressure and high relative humidity at the top of
    12·1 answer
  • When a moving car is brought to a stop with the brakes, its acceleration vector is 29. (a) in the same direction as its velocity
    6·1 answer
  • a uniform rod of length 1.5m is placed over a wedge at 0.5m from one end .a force of 100 N is applied at its one end near the we
    14·1 answer
  • An airplane flies 2500 miles east in 245 seconds what is the velocity of the plane?
    7·1 answer
  • NEED HELP IS THERE SOMEONE CAN HELP ME PLS :)
    6·1 answer
  • A certain heat engine does 30.2 kJ of work and dissipates 9.14 kJ of waste heat in a cyclical process.
    15·1 answer
  • A cheetah goes from 0 m/s to 25 m/s in 2.5s. what is the cheetahs rate of acceleration? A. 10m/s2
    15·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!