Question

the speed of a body moving along a straight path decrease from 10m/s to 5m/s in 2sec find the deceleration​

Answer 1

Given :

▪ Initial speed = 10mps

▪ Final speed = 5mps

▪ Time interval = 2s

To Find :

▪ Deceleration of body.

Concept :

⭐ Acceleration is defined as the rate of change in velocity(speed).

⭐ It is a vector quantity.

⭐ It can be positive, negative or zero.

⭐ It has both magnitude as well as direction.

⭐ SI unit : m/s²

Calculation :

$\twoheadrightarrow\tt\:a=\dfrac{v-u}{t}\\ \\ \rightarrowtail\tt\:a=\dfrac{5-10}{2}\\ \\ \twoheadrightarrow\tt\:a=\dfrac{-5}{2}\\ \\ \rightarrowtail\underline{\boxed{\tt{\blue{a=-2.5\:ms^{-2}}}}}\:\orange{\bigstar}$

[Note : -ve sign shows retardation.]

Answer 2

Answer:

2.5 m/s

Explanation:

initial velocity (u) = 10m/s

final velocity (v) = 5m/s

time (t) = 2 sec

acceleration (a) = ?

Therefore,

v = u + at

5 = 10 + 2a

5-10 = 2a

2a = -5

a = -2.5

Acceleration = -2.5 m/s^2

Deceleration/Retardation = 2.5 m/s^2