Question

An object accelerates at a rate of -1.2 m/s² to a velocity of 32 m/s over a time of 15 s. What was its initial velocity?

A) -31.8 m/s
B) -21.8 m/s
C) -11.8 m/s
D) -1.8 m/s

Answer 1

Using the formula v = u + at where v is the final velocity, u is the initial velocity, a is the acceleration, and t is the time, the initial velocity is calculated to be 50 m/s, although this doesn't exactly match the calculated result.

Step-by-step explanation:

To solve for the initial velocity of the object, we can use the formula that relates velocity, acceleration, and time:

v = u + at

Where:

• v is the final velocity
• u is the initial velocity
• a is the acceleration
• t is the time

We're given that the final velocity (v) is 32 m/s, the acceleration (a) is -1.2 m/s², as it's a deceleration, and the time (t) is 15 s. Plugging in these values, we get:

32 m/s = u + (-1.2 m/s² * 15 s)

Simplify the equation:

32 m/s = u - 18 m/s

Add 18 m/s to both sides:

32 m/s + 18 m/s = u

u = 50 m/s

The initial velocity is calculated to be 50 m/s, although this doesn't exactly match the calculated result.