Question

9. A car traveling at 15 m/s starts to decelerate steadily. It comes to a complete stop in 10 seconds. What is it’s acceleration?

Answer 1

Explanation:

initial velocity = 15 m/s

final velicity = 0 m/s

time required = 10sec

Formula is V = U + at

0 = 15 + a 10

-15 ÷ 10 = acc

acc = - 1.5 m/s^2

Answer 2

Given :

• v ( final velocity ) = 0 m/s
• u ( initial velocity ) = 15 m/s
• t ( time ) = 10 sec

To find :

• Acceleration

Solution :

We know that,

$\boxed{\rm{\red{a\:=\:\dfrac{v\:-\:u}{t}}}}$

: $\implies$ a = $\dfrac{0\:-\:15}{10}$

: $\implies$ a = -1.5 m/s²

[ here negative sign shows opposite direction ]

Hence, acceleration is -1.5 m/s²

$\rule{200}2$

• Acceleration is the rate of change of velocity.

• Its S.I unit is m/s².

• It is of three types :

★ Negative acceleration

★ positive acceleration

★zero acceleration