Question

A motorcycle starts from rest and accelerates along a straight path at 2 ms^-2 at the starting point of the motorcycle There is a stationary electric siren. How far has the motorcycle gone when the driver here is the frequency of the siren and 94 % of its value when the motorcycle was at rest ?
a) 196m b) 49m c) 98m d) 147m​

Answer 1

Answer:

Correct option is (c) 98m

Given that,

Acceleration = 2m/s^2.

94% of siren is heard to driver.

To find,

How far has the motorcycle gone when the driver here is the frequency of the siren and 94 % of its value when the motorcycle was at rest ?

Solution:

For motorcycle u = 0, a = 2m/s^-2

n’ = n(v - v₀)/(v + v₁)

(94/100)n = n(330 - v₀)/330

330 - v₀ = (330*94)/100

v₀ = 330 - (94*33)/10

v₀ = (33*6)/10 m/s

To find the displacement using velocity, the formula is

S = (v^2 - u^2)/2a

S = (9*33*33)/100

S = (9*1089)/100

S = 9801/100

S = 98.01

S ≈ 98m