Question

a body of mass10 kg is moving with a constant velocity of 10 m/ s. when a constant force acts for 4 sec on it ,it moves with a velocity 2 m/sec in the opposite direction. the acceleration produced in it is​

Answer 1

Solution:

Given:

=> Mass of an object = 10 kg

=> Initial velocity = 10 m/s

=> Final velocity = -2 m/s [Opposite Direction]

=> Time = 4 sec

To find:

=> Acceleration

Formula used:

$\sf{\implies Acceleration = \dfrac{v-u}{t}}$

So,

We know that,

$\sf{\implies Acceleration = \dfrac{Final\;Velocity - Initial\;Velocity}{Time\;taken}}$

$\sf{\implies \dfrac{v-u}{t}}$

$\sf{\implies \dfrac{-2-10}{4}}$

$\sf{\implies \dfrac{-12}{4}}$

${\boxed{\boxed{\sf{\implies Acceleration = -3\;m/s^{2}}}}}$

∴ Acceleration is negative. It means it is retardation.

Answer 2

Answer:

${\bold{\therefore Acceleration=-3\:m/s^{2}(retardation)}}$

Explanation:

$\huge{\bold{\underline{\underline{SOLUTION-}}}}$

• In the given question information given about a body of mass and its velocity is given. After 4 sec it moves with another velocity with opposite direction.

• We have to find the acceleration of body.

$\underline \bold{Given : } \\ \implies Mass \: of \: body = 10 \: kg \\ \\ \implies Initial \: velocity(u) = 10 \: m/s \\ \\ \implies Final \: velocity(v) =- 2 \: m/s\:\: (oppsite\:direction)\\ \\ \implies Time(t) = 4 \: sec \\ \\ \underline \bold{To \: Find : } \\ \implies Acceleration(a) = ?$

• According to given question :

$\bold{By \: first \: equation \: of \: motion : } \\ \implies v = u + at \\ \\ \implies -2 = 10 + a \times 4 \\ \\ \implies -2 - 10 = 4a \\ \\ \implies - 12= 4a \\ \\ \implies a = \frac{ \cancel{- 12}}{ \cancel4} \\ \\ \bold{\implies a = - 3 \: m /{s}^{2} } \\ \\ \bold{\therefore acceleration\: of \: -3 \: m /{s}^{2}(retardation)}$