Acar accelerates from rest at -2.50 m/s². (include the sign in your answers.)
what is the velocity at the end of 3.1 s?

v = -7.75 m/s

Explanation:

given,

acceleration of car = - 2.5 m/s²

velocity of the car at t = 3.1 s = ?

initial speed of the car (u)= 0 m/s

using equation of motion

v = u + a t

v =0  +(-2.5) x 3.1

v = -2.5 x 3.1

v = -7.75 m/s

negative sign represent the direction of motion.

hence, speed of the velocity at the end of the 3.1 s is equal to   v = -7.75 m/s

hypothesising or postulating

we need to know the time interval during which the force acts. impulse of force = momentum change