(b) Determine the acceleration at t = 2.0 s. SOLUTION (Use the following as necessary: t and At.) Knowing that the initial velocity at any time t is v, xi (39 – 0.8t2) m/s, find the velocity at any later time t + At: m/s Find the change in velocity over the time interval At: Δν. m/s To find the acceleration at any time t, divide this expression by At and take the limit of the result as At approaches zero: Av a = lim At-0 m/s? Δε Substitute t = 2.0 s (Enter your answer in m/s. Indicate the direction with the sign of your answer.): m/s?

(b) Determine the acceleration at t = 2.0 s. SOLUTION (Use the following as necessary: t and At.) Knowing that the initial velocity at any time t is v, xi (39 – 0.8t2) m/s, find the velocity at any later time t + At: m/s Find the change in velocity over the time interval At: Δν. m/s To find the acceleration at any time t, divide this expression by At and take the limit of the result as At approaches zero: Av a = lim At-0 m/s? Δε Substitute t = 2.0 s (Enter your answer in m/s. Indicate the direction with the sign of your answer.): m/s?