Question

A car accelerates uniformly from an initial velocity of 2 m/s to final velocity 10m/ਸ in 8 s. It then slows down uniformly to a final velocity 4m/s in 6s calculate the accelaertion in first 8s and last 6

Answer 1

ANSWER:

➡Acceleration in 1st 8 seconds

= 1 m/s²

= 1 m/s²➡ Retardation produced by brakes in last 6 seconds

= 1 m/s²➡ Retardation produced by brakes in last 6 seconds = -1 m/s²

Explanation:

given that,

A car accelerates uniformly from an initial velocity of 2 m/s to final velocity 10m/s in 8 s

here,

initial velocity of the the car = 2m/s

final velocity of car = 10 m/s

time taken for accelerating = 8 seconds

by the equation of motion

v = u + at

initial velocity(u) = 2 m/s

final velocity (v) = 10 m/s

time = 8 seconds

putting the values,

10 = 2 + a(8)

10 = 2 + 8a

8a = 10 - 2

8a = 8

a = 8/8

a = 1 m/s²

acceleration in 1st 8 seconds =

1 m/s²

now,

also given that,

It then slows down uniformly to a final velocity 4m/s in 6s

so,

here,

initial velocity of car (u) = 10 m/s

final velocity of car (v) = 4 m/s

time for deceleration (t) = 6 s

now,

by the motion equation,

v = u + at

putting the values

4 = 10 + a(6)

6a + 10 = 4

6a = 4 - 10

6a  = -6

a = -6/6

a = -1 m/s²

negative acceleration shows the Retardation .

so,

Retardation produced by brakes in last 6 seconds = -1 m/s²

ANSWER:

➡Acceleration in 1st 8 seconds

= 1 m/s²

➡ Retardation produced by brakes in last 6 seconds

= -1 m/s²