Question

the velocity of an object increases at a constant rate from 30m/s to 70m/s comes to stop in 7s. Find the acceleration.​

Answer 1

$\huge \mathbb{\boxed{\red{Question\:}}}$

The velocity of an object increases at a constant rate from 30m/s to 70m/s comes to stop in 7s. Find the acceleration.

$\huge \mathbb{\boxed{\red{Solution\:}}}$

u = 70m/s ; v = 0 [ because as we know that if an object comes to rest than v = 0 ] ; t = 7sec

We have to use the first equation of motion.

➣ v = u + at

➣ 0 = 70 + 7t

➣ 7t = -70

➣ t = -70/7

➣ t = -10 m/s²

( Or )

We can you the acceleration formula also to find.

$\ \mathbb{\boxed{{a = \frac{v \: - u}{t}\:}}}</p><p>$

➣ a = ( 0 - 70 )/7

➣ a = -70/7

➣ a = -10 m/s²