Question

7. If final velocity is greater than initial velocity, the velocity with time and the value of acceleration is a. Increases, negative b. Decreases, positive c. Increases, positive d. Decreases, zero​

Answer 1

Answer:

c) increased, positive

Answer 2

Explanation:

First, let us make some simplifications in notation. Taking the initial time to be zero, as if time is measured with a stopwatch, is a great simplification. Since elapsed time is Δt = tf−t0, taking t0 = 0 means that Δt = tf, the final time on the stopwatch. When initial time is taken to be zero, we use the subscript 0 to denote initial values of position and velocity. That is, x0 is the initial position and v0 is the initial velocity. We put no subscripts on the final values. That is, t is the final time, x is the final position, and v is the final velocity. This gives a simpler expression for elapsed time—now, Δt=t. It also simplifies the expression for displacement, which is now Δx = x−x0. Also, it simplifies the expression for change in velocity, which is now Δv = v−v0. To summarize, using the simplified notation, with the initial time taken to be zero,

\displaystyle \begin{cases}{\Delta}{t} &=& t \\{\Delta}{x} &=& x-{{x}_{0}}\\{\Delta}{v} &=& v-{{v}_{0}}\end{cases}⎩⎪⎨⎪⎧ΔtΔxΔv===tx−x0v−v0

where the subscript 0 denotes an initial value and the absence of a subscript denotes a final value in whatever motion is under consideration.