Question
e) A body moves in a straight line so that its distance S meters from a fixed point 0 at time t seconds is given by S=(t-2)^2(2t-7) Find the time when the body passes through point 0 and the acceleration each time it passes through 0. (3 Marks)
Solution
4.3
(296 Votos)
Wilma
Veterano · Tutor por 11 anos
Resposta
To find the time when the body passes through point 0, we need to set the distance S equal to 0 and solve for t.
This equation is satisfied when either
or
.
gives
.
gives
.So, the body passes through point 0 at
seconds and
seconds.To find the acceleration each time the body passes through 0, we need to take the second derivative of the position function S(t) with respect to t.
Taking the first derivative:
Taking the second derivative:
Now, we can evaluate the acceleration at the times when the body passes through point 0:At
seconds:
m/s²At
seconds:
m/s²Therefore, the acceleration each time the body passes through point 0 is -6 m/s² at
seconds and 12 m/s² at
seconds.