Question

An object with a mass 5 kg moves at a constant velocity
of 8 m/s. A constant force then acts for
6 seconds on the object giving it a speed of
4 m/s in opposite direction. The acceleration produced
is :-
(1) 1.5 m/s2
(2) -2 m/s2
(3) 0.67 m/s2
(4) -0.5 m/s2

Answer 1

Answer:

$\sf{(2)\: -2 {ms}^{-2}}$

Explanation -

Given -

• Mass of the object (m) = 5 kg
• Initial velocity of the object (u) = 8 m/s
• Time for which force acts (t) = 6s
• Final velocity of the object, v = -4 m/s

( Here we took the final velocity negative because of the opposite direction ).

To find -

• Acceleration produced on the object

Solution -

$\\ \star \: \large{ \underline{ \boxed{ \sf{v = u + at}}}} \\ \\ \\ \implies \sf \: - 4 = 8 + 6a \\ \\ \\ \implies \sf \: 6a = 8 + ( - 4) \\ \\ \\ \implies \sf \: 6a = - 12 \\ \\ \\ \implies \sf \: a = \dfrac{12}{6} \\ \\ \\ \implies \: \sf{ \underline{ - 2 \: m {s}^{ - 2} }}$

Therefore, the acceleration produced on the object is -2m/s²

Answer 2

$\huge\bold{Answer:-}$

Option B : -2 m/s²

Explanation:

Given -

Mass = 5 kg

Initial Velocity ( u ) = 8 m/s²

Final Velocity ( v ) = - 4 m/s²

Time ( t ) = 6 seconds

Acceleration ( a ) = ?

☆ To find acceleration -

${v = u + at}$

Here, ${a}$ is acceleration, ${v}$ is final velocity, ${u}$ is initial velocity and ${t}$ is time.

=> −4 = 8 + 6a

=> 6a = 8 + ( −4 )

=> 6a = −12

=> a = −12 / 6

=> −2 ms²

Acceleration is a vector quantity defined as the rate at which an object changes its velocity. An object is accelerating if it's changing its velocity.