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
Yanka [14]
3 years ago
12

To meet a U.S. Postal Service requirement, employees' footwear must have a coefficient of static friction of 0.5 or more on a sp

ecified tile surface. A typical athletic shoe has a coefficient of 0.830. In an emergency, what is the minimum time interval in which a person starting from rest can move 3.20 m on a tile surface if she is wearing the following footwear?
Physics
1 answer:
motikmotik3 years ago
8 0

Answer:

0.79 s

Explanation:

We have to calculate the employee acceleration, in order to know the minimum time. According to Newton's second law:

\sum F_x:f_{max}=ma_x\\\sum F_y:N-mg=0

The frictional force is maximum since the employee has to apply a maximum force to spend the minimum time. In y axis the employee's acceleration is zero, so the net force is zero. Recall that f_{max}=\mu N

Now, we find the acceleration:

\mu N=ma_x\\\mu mg=ma_x\\a_x=\mu g\\a_x=0.83(9.8\frac{m}{s^2})\\a_x=8.134\frac{m}{s^2}

Finally, using an uniformly accelerated motion formula, we can calculate the minimum time. The employee starts at rest, thus his initial speed is zero:

x=v_0t+\frac{1}{2}a_xt^2\\2x=a_xt^2\\t=\sqrt{\frac{2x}{a}}\\t=\sqrt{\frac{2(3.2m)}{8.134\frac{m}{s^2}}}\\t=0.79 s

You might be interested in
Every atom of an element has the same _____.
kirill [66]
The same number of protons. brainliest?(:
4 0
3 years ago
Read 2 more answers
Which purpose does a light bulb serve in a circuit?
aliina [53]

Answer:

A light bulb is that component of circuit that lights up when electricity flows through it and vice versa. Its main function is to tell whether electricity is being supplied or not. Its function is also to light up dark places.

Explanation:

7 0
2 years ago
Read 2 more answers
A cylindrical tube sustains standing waves at the following frequencies: 600 Hz, 800 Hz, and 1000 Hz. The tube does not sustain
Thepotemich [5.8K]

Answer:

Explanation:

In  closed organ pipe notes with odd harmonics are produced and in open organ pipe notes with all odd and even harmonics are produced. notes with frequencies 600, 800 and 1000 Hz are produced. These are 3 , 4 and 5 times 200 Hz. ie both odd and even times of 200 . So fundamental frequency appears to be 200 Hz. There is no note available between 800 and 1000. It also indicates that 200 Hz is the fundamental frequency and the pipe is open at both ends.

3 0
3 years ago
A motorcyclist drove 7 km at 57km/h and then another 7 km at 81 km/h. What was the average speed? ​
alex41 [277]

<u>Answer:</u>

<em>The average speed of the car is 66.9 km/h</em>

<u>Explanation:</u>

Here distance covered with the speed <em>57 km/h=7 km  </em>

distance covered with the speed of <em>81 km/h=7 km</em>

<em>Average speed is equal to the ratio of total distance to the total time. </em>

<em>total distance= 7 + 7= 14 km  </em>

<em>time= \frac{distance}{speed} </em>

<em>time taken to cover the first 7 km= 7/57 h  </em>

<em>time taken to cover the second part of the journey = 7/81 h </em>

<em>average speed =  14/(7/57+7/81)=(14 \times 57 \times 81)/945=66.9 km/h</em>

<u><em>Shortcut: </em></u>

<em>When equal distances are covered with different speeds average speed=2 ab/(a+b) where a and b are the variable speeds in the phases. </em>

7 0
3 years ago
A boy throws a snowball straight up in the air with an initial speed of 4.50 ft/s from a position 4.00 ft above the ground. The
IgorC [24]

Answer:

a) 0.658 seconds

b) 0.96 inches

Explanation:

v=u+at\\\Rightarrow 0=4.5-32.1\times t\\\Rightarrow \frac{-4.5}{-32.1}=t\\\Rightarrow t=0.14 \s

Time taken by the ball to reach the highest point is 0.14 seconds

s=ut+\frac{1}{2}at^2\\\Rightarrow s=4.5\times 0.14+\frac{1}{2}\times -32.1\times 0.14^2\\\Rightarrow s=0.315\ ft

The highest point reached by the snowball above its release point is 0.315 ft

Total height the snowball will fall is 4+0.315 = 4.315 ft

s=ut+\frac{1}{2}at^2\\\Rightarrow 4.315=0t+\frac{1}{2}\times 32.1\times t^2\\\Rightarrow t=\sqrt{\frac{4.315\times 2}{32.1}}\\\Rightarrow t=0.518\ s

The snowball will reach the bank at 0.14+0.518 = 0.658 seconds after it has been thrown

v=u+at\\\Rightarrow v=0+32.1\times 0.518\\\Rightarrow v=16.62\ ft/s

v^2-u^2=2as\\\Rightarrow s=\frac{v^2-u^2}{2a}\\\Rightarrow s=\frac{0^2-16.62^2}{2\times -100\times 3.28}\\\Rightarrow s=0.42\ ft

The snowball goes 0.5-0.42 = 0.08 ft = 0.96 inches

8 0
3 years ago
Other questions:
  • Can objects in a system have momentum while the momentum of the system is zero? explain your answer.
    12·1 answer
  • Which one of the following bodies has only potential energy?
    8·1 answer
  • Consider the diver and the board. Which object exerts the action force?
    5·2 answers
  • How does an electric field change due to voltage?
    8·1 answer
  • Disk A, with a mass of 2.0 kg and a radius of 60 cm , rotates clockwise about a frictionless vertical axle at 20 rev/s . Disk B,
    8·1 answer
  • When is the potential energy of a pendulum at its greatest?
    5·1 answer
  • You walk 4.5 km in one direction then make a 45 degree turn to the right and walk another 6.4 km what is the magnitude of your d
    14·1 answer
  • Our solar system is made up of the Sun, 8 planets, and other bodies such as
    14·1 answer
  • What are 3 things that continental drifts have that plate tectonics dont
    9·1 answer
  • A push on a 1-kg brick accelerates it. Neglecting friction, equally accelerating a 10-kg brick requires 10 times as much force.
    11·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!