1.If a body moves in a straight line according to the law s= 24t +3t^2 - t³, where s is the distance measured in meters from the origin and t is the time in seconds after it starts to move, calculate the body’s velocity as a function of time.

Question

a.v = 30t – 3t²
b.v= 30t - t²
c.v = 24 + 3t- t^2
d.v = 24 +6t -3t²

I think it's D but also confused by A


2.what is the velocity of the body in question 10 when t = 3seconds?

a.15 m/s
b.27 m/s
c.63 m/s
d.81 n/s

I think it's A but confused it might by C.

can you help me .

Answer 1

1) D
2) v = 24 +6t -3t²
when t = 3
v = 24 +18 - 27
v = 15 or in other words a.

Answer 2

thank you!