Question

If a bus travelling at 20 m/s is subject to a steady deceleration of 5m/s2 ,how long will it take to come to rest?

Answer 1

QUESTION:

If a bus travelling at 20 m/s is subject to a steady deceleration of 5m/s2 ,how long will it take to come to rest?

ANSWER:

Time = 4 seconds

Explanation:

given that,

a bus travelling at 20 m/s

so,

here,

initial velocity of bus = 20 m/s

given

the deceleration of bus = 5 m/s²

since,

deceleration is always negative,

so,

deceleration of bus = -5 m/s²

the bus stops ,

so,

final velocity of bus will 0

now,

we have

initial velocity(u) = 20 m/s

final velocity(v) = 0

deceleration(a) = -5 m/s²

by the equation of motion

v = u + at

now,

putting the values,

0 = 20 + -5t

-5t = -20

t = -20/-5

t = 4 seconds

so,

when the bus travelling at 20 m/s is subject to a steady deceleration of 5m/s²

then the bus will take 4 seconds

to come in rest

so,

Time = 4 seconds

Answer 2

$\huge\boxed{Answer:-}$

Note•°•

• 4 seconds is the time taken.
• 20 m/s the bus travelling.
• 20 m/s is the Initial velocity of bus.
• 5 m/s² is deceleration of bus.
• 0 is the bus final velocity

= 20 m/s

0=f

d= -5 m/s²

By the Equation:-

v = u + at

Adding the values:

0 = 20 + -5t

-5t = -20

$t = \frac{20}{- 5}$

t = 4 sec

Therefore the answer

$\huge\boxed{t= 4 seconds}$