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
VLD [36.1K]
3 years ago
11

a bus is moving with the velociity of 36 km/hr . after seeing a boy at 20 m ahead on the road, the driver applies the brake and

the bus gets stopped at 10 m distance. Now, calculate acceleration as well as time taken by this bus to stop.​
Physics
1 answer:
Klio2033 [76]3 years ago
8 0

Answer:

Assumption: the acceleration of this bus is constant while the brake was applied.

Acceleration of this bus: approximately \left(-6.0\; \rm m \cdot s^{-2}\right).

It took the bus approximately 1.7\;\rm s to come to a stop.

Explanation:

Quantities:

  • Displacement of the bus: x = 10\; \rm m.
  • Initial velocity of the bus: \displaystyle u = 36\; \rm km \cdot hr^{-1} = 36\; \rm km \cdot hr^{-1}\times \frac{1\; \rm m \cdot s^{-1}}{3.6\; \rm km\cdot hr^{-1}} = 10\; \rm m \cdot s^{-1}.
  • Final velocity of the bus: v = 0\; \rm m\cdot s^{-1} because the bus has come to a stop.
  • Acceleration, a: unknown, but assumed to be a constant.
  • Time taken, t: unknown.

Consider the following SUVAT equation:

\displaystyle x = \frac{1}{2}\, \left(a\, t^2\right) + u\, t.

On the other hand, assume that the acceleration of this bus is indeed constant. Given the initial and final velocity, the time it took for the bus to stop would be inversely proportional to the acceleration of this bus. That is:

\displaystyle t = \frac{v - u}{a}.

Therefore, replace the quantity t with the expression \displaystyle \left(\frac{v - u}{a}\right) in that SUVAT equation:

\displaystyle x = \frac{1}{2}\, \left(a\, \left(\frac{v -u}{a}\right)^2\right) + u\, \left(\frac{v - u}{a}\right).

Simplify this equation:

\begin{aligned}x &= \frac{1}{2}\, \left(a\, {\left(\frac{v -u}{a}\right)}^2\right) + u\, \left(\frac{v - u}{a}\right) \\ &= \frac{1}{2}\left(\frac{{(v - u)}^2}{a}\right) + \frac{u\, (v - u)}{a} =\frac{1}{a}\, \left(\frac{{(v - u)}^2}{2} + u\, (v - u)\right)\end{aligned}.

Therefore, \displaystyle a= \frac{1}{x}\, \left(\frac{{(v - u)}^2}{2} + u\, (v - u)\right).

In this question, the value of x, u, and v are already known:

  • x = 10\; \rm m.
  • \displaystyle u =10\; \rm m \cdot s^{-1}.
  • v = 0\; \rm m\cdot s^{-1}.

Substitute these quantities into this equation to find the value of a:

\begin{aligned} a &= \frac{1}{x}\, \left(\frac{{(v - u)}^2}{2} + u\, (v - u)\right) \\ &= \frac{1}{10\; \rm m}\times \left(\frac{{\left(0\; \rm m \cdot s^{-1} - 10\; \rm m \cdot s^{-1}\right)}^2}{2} + \left(0\; \rm m \cdot s^{-1} - 10\; \rm m \cdot s^{-1}\right)\times 10\; \rm m \cdot s^{-1}\right)\\ &\approx -6.0\; \rm m \cdot s^{-2}\end{aligned}.

(The value of acceleration a is less than zero because the velocity of the bus was getting smaller.)

Substitute a \approx -6.0\; \rm m \cdot s^{-2} (alongside u = 10\; \rm m \cdot s^{-1} and v = 0\; \rm m \cdot s^{-1}) to estimate the time required for the bus to come to a stop:

\begin{aligned}t &= \frac{v - u}{a} \\ &\approx \frac{0\; \rm m \cdot s^{-1} - 10\; \rm m \cdot s^{-1}}{-6.0\; \rm m \cdot s^{-2}} \approx 1.7\; \rm s\end{aligned}.

You might be interested in
The attraction or repulsion of two objects is called blank force what is the blank
AysviL [449]

Answer:

Coulomb Force

Explanation:

Coulomb force, also called electrostatic force or Coulomb interaction, attraction or repulsion of particles or objects because of their electric charge.

5 0
3 years ago
What are the products in the reaction in the introduction above? Select all that apply.
WARRIOR [948]

Answer:

h2o and o2

Explanation:

3 0
3 years ago
Someone pls help me will give brainlist
Crazy boy [7]

Answer:

The volume is 5.6 L

The mass is 100.2g

Explanation:

Quantitative observations are more based on numbers and values

6 0
3 years ago
Which two statements are true of electromagnetic waves?
Usimov [2.4K]

Answer:

B and C

Explanation:

Because EMWs are varying magnetic and electric radiation traveling at 90° to each other propagating energy form one place to another through vibration of these magnetic and electric fields

3 0
3 years ago
Answer please in comment what i am typing​
qwelly [4]

Answer:

Hiiiiiiii........where r u frm??

3 0
3 years ago
Other questions:
  • What is the benefit of using the metric system and SI Units? Question 1 options: to measure accurately on equipment to convey in
    7·1 answer
  • Why machines are never 100 percent efficient
    13·2 answers
  • Jamal combined baking soda and vinegar but he is having trouble determining if what he observed is a chemical reaction or a phys
    15·2 answers
  • What are 3 wave properties?
    7·2 answers
  • How do magnetic forces repel or attract?<br> Plz make it as simple as possible
    9·1 answer
  • A child with mass 40 kg sits on the edge of a merry-go-round at a distance of 3.0 m from its axis of rotation. The merry-go-roun
    9·1 answer
  • Let's practice calculating the frictional force of a skier on old "woody" skis and wet snow. The skier has a mass of 58 kg. The
    13·1 answer
  • Do simple sugars provide short term energy?
    13·2 answers
  • Is the normal force equivalent to the weight of an object?
    13·1 answer
  • A cylindrical wire of radius 2 mm carries a current of 3.0 A. The potential difference between points on the wire that are 44 m
    8·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!