Question

A block of mass 3 kg has a velocity of u m / s . When a force of 18 N acts on the block it reduces the velocity from u to u / 2 after the block has covered a distance of 9.0 m . Find u .​

Answer 1

Answer:

ATQ,

mass = 3 kg, force= 18N

initial velocity= u m/ s

final velocity ,v = u/2 m/ s

As we know that F= ma

acc. to Newton's first law of motion...

F = ma

18 kg m/ s²=( 3kg )a. , a= 6 m/s²

As we know that v²- u² = 2as

S is given ie 9 m

V²- U²= 2AS

( U/2)² - U² = 2× 6 × 9

-3U²/4 = 108

-U² = 144

- U = +12 , -12

-U = -12

: U= 12M/ S :::

answer is

u = 12m/ s