Question

1. The acceleration equation of a certain particle is a=2t, after 4s, its velocity reaches 20m/s, then the initial velocity of the particle movement is ) ms B Sms 2.​

Answer 1

Change in velocity is the integral of all the differential accelerations acting over the period of acceleration.

`20 = u + \int\limits^4_0 {2t} \, dt`

20 = u + t²
`\left \{ {{4} \atop {0}} \right.`

20 = u + 4² - 0²

20 = u + 16

u = 4 m/s