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
guajiro [1.7K]
3 years ago
13

In a race, Usain Bolt accelerates at

Physics
1 answer:
jeka943 years ago
3 0

Answer:

65.87 s

Explanation:

For the first time,

Applying

v² = u²+2as.............. Equation 1

Where v = final velocity, u = initial velocity, a = acceleration, s = distance

From the question,

Given:  u = 0 m/s (from rest), a = 1.99 m/s², s = 60 m

Substitute these values into equation 1

v² = 0²+2(1.99)(60)

v² = 238.8

v = √238.8

v = 15.45 m/s

Therefore, time taken for the first 60 m is

t = (v-u)/a............ Equation 2

t = (15.45-0)/1.99

t = 7.77 s

For the final 40 meter,

t = (v-u)/a

Given: v = 0 m/s(decelerates), u = 15.45 m/s, a = -0.266 m/s²

Substitute into the equation above

t = (0-15.45)/-0.266

t = 58.1 seconds

Hence total time taken to cover the distance

T = 7.77+58.1

T = 65.87 s

You might be interested in
Calculate the weight of a new fast-food sandwich that has a mass of 0.1 kg (approximately the mass of a quarter pound). Think of
iragen [17]

Weight = (mass) x (gravity)

If you plan to sell these things on Earth, then the acceleration of gravity in the neighborhood of your drive-throughs will be 9.81 m/s².

Weight of each sandwich = (0.1 kg) x (9.81 m/s²).

Weight of each sandwich = 0.981 Newton.

This is only  1.9%  less than 1 even Newton.

You should start by setting up one restaurant in New York, one in Chicago, one in LA, and maybe one in Miami or Tulsa.  Sell it with a different name in each place, and see which name sells best.

You might want to try calling it

-- Isaac's burger

-- Gravity grub

-- Prism Patty

-- Mass 'o Meat

-- Unit-wich

and see if anything catches on.

I think I'd simply call it a "Newton Unit".

5 0
3 years ago
Why is energy transferred from the substance to the surroundings when a substance freezes
jeyben [28]
Zalice sucks chakra woman trAnsfer to the fezze y try e
7 0
3 years ago
Starting from rest, a disk rotates about its central axis with constant angular acceleration. In 1.00 s, it rotates 21.0 rad. Du
ELEN [110]

With constant angular acceleration \alpha, the disk achieves an angular velocity \omega at time t according to

\omega=\alpha t

and angular displacement \theta according to

\theta=\dfrac12\alpha t^2

a. So after 1.00 s, having rotated 21.0 rad, it must have undergone an acceleration of

21.0\,\mathrm{rad}=\dfrac12\alpha(1.00\,\mathrm s)^2\implies\alpha=42.0\dfrac{\rm rad}{\mathrm s^2}

b. Under constant acceleration, the average angular velocity is equivalent to

\omega_{\rm avg}=\dfrac{\omega_f+\omega_i}2

where \omega_f and \omega_i are the final and initial angular velocities, respectively. Then

\omega_{\rm avg}=\dfrac{\left(42.0\frac{\rm rad}{\mathrm s^2}\right)(1.00\,\mathrm s)}2=42.0\dfrac{\rm rad}{\rm s}

c. After 1.00 s, the disk has instantaneous angular velocity

\omega=\left(42.0\dfrac{\rm rad}{\mathrm s^2}\right)(1.00\,\mathrm s)=42.0\dfrac{\rm rad}{\rm s}

d. During the next 1.00 s, the disk will start moving with the angular velocity \omega_0 equal to the one found in part (c). Ignoring the 21.0 rad it had rotated in the first 1.00 s interval, the disk will rotate by angle \theta according to

\theta=\omega_0t+\dfrac12\alpha t^2

which would be equal to

\theta=\left(42.0\dfrac{\rm rad}{\rm s}\right)(1.00\,\mathrm s)+\dfrac12\left(42.0\dfrac{\rm rad}{\mathrm s^2}\right)(1.00\,\mathrm s)^2=63.0\,\mathrm{rad}

5 0
3 years ago
When a condenser discharges electricity, the instantaneous rate of change of the voltage is proportional to the voltage in the c
e-lub [12.9K]

Answer:

460.52 s

Explanation:

Since the instantaneous rate of change of the voltage is proportional to the voltage in the condenser, we have that

dV/dt ∝ V

dV/dt = kV

separating the variables, we have

dV/V = kdt

integrating both sides, we have

∫dV/V = ∫kdt

㏑(V/V₀) = kt

V/V₀ = e^{kt}

Since the instantaneous rate of change of the voltage is -0.01 of the voltage dV/dt = -0.01V

Since dV/dt = kV

-0.01V = kV

k = -0.01

So, V/V₀ = e^{-0.01t}

V = V₀e^{-0.01t}

Given that the voltage decreases by 90 %, we have that the remaining voltage (100 % - 90%)V₀ = 10%V₀ = 0.1V₀

So, V = 0.1V₀

Thus

V = V₀e^{-0.01t}

0.1V₀ = V₀e^{-0.01t}

0.1V₀/V₀ = e^{-0.01t}

0.1 = e^{-0.01t}

to find the time, t it takes the voltage to decrease by 90%, we taking natural logarithm of both sides, we have

㏑(0.01) = -0.01t

So, t = ㏑(0.01)/-0.01

t = -4.6052/-0.01

t = 460.52 s

3 0
3 years ago
What force could be applied to a box to make the net force in the horizontal direction of zero​
Kazeer [188]

If there is no friction, the force that moves the box forward horizontally must be matched by the same force.

If there is friction, then the force moving it forward = frictional force + the additional force you need to add.

6 0
3 years ago
Other questions:
  • When a system absorbs heat from its surroundings it is a(n) ____ process
    9·1 answer
  • What is the momentum of an object that is traveling at 3 m/s and has a mass of 5 kg?
    5·1 answer
  • A surface is bombarded by particles, each of mass small 'm', which have velocity
    5·1 answer
  • Which activity best demonstrates Ernest Rutherford's creativity?A. questioning the correctness of the plum pudding modelB. desig
    14·1 answer
  • The force it would take to accelerate a 900-kg car at a rate of 3 m/s2 is
    10·2 answers
  • Latent heat of fusion refers to which changes of state?
    11·1 answer
  • In terms of their location, what is the difference between subcutaneous fat and visceral fat
    7·1 answer
  • I can't understand
    11·1 answer
  • Explain the concept of energy conversion as applied to the generation of electricity also known as electrical energy.​
    9·1 answer
  • if your oven uses a 220.0 volt line and draws a maximum 8.00 A current what is the resistance of the oven when it is fully heate
    15·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!