Question

a cyclist leaves her home and travels along a straight road.She accelerates to a speed of 12ms-¹ in the first 5 s. Then she travels at a constant speed for a further 17s. A cat jumps out onto the road and she immediately applies brakes and slows down uniformly before coming to a rest.Total motion takes 26s.Calculate the value of acceleration in the first 5s.​

Answer 1

Given :

Initial velocity = zero

Final velocity after 5s = 12 m/s

To Find :

Acceleration of cyclist during first 5 seconds.

Solution :

■ Acceleration is measured as the rate of change of velocity.

Mathematically, $\underline{\boxed{\bf{\orange{a=\dfrac{v-u}{t}}}}}$

• It is a vector quantity having both magnitude as well as direction.
• It can be positive, negative or zero.
• SI unit : m/s
• CGS unit : cm/s²

By substituting the given values,

$:\implies\tt\:a=\dfrac{v-u}{t}$

$:\implies\tt\:a=\dfrac{12-0}{5}$

$:\implies\tt\:a=\dfrac{12}{5}$

$:\implies\:\underline{\boxed{\bf{\gray{a=2.4\:ms^{-2}}}}}$