Question

A particle moving with a constant acceleration has a velocity of 20 cm/s when its position is x = 10 cm. Its position 4.0 s later is x = - 30 cm. What is the acceleration of the particle? Select one: A. 5.0 cm/s2 B. 15 cm/s2 O C. 10 cm/s2 D. - 15 cm/s2 O E. - 5.0 cm/s2

Answer 1

Given that the initial velocity is v = 20cm/ sec, and t=4s

So now change in the position

dx = x_2 - x_1 = -30-10 = 40 cm

Now from the Newton's third equation

dx = v*t+(at^2) /2

-40 = 20*4+(16a) /2

-120*2/16= a= -15 cm/s²

So the acceleration A= -15 cm/s²